Changelog

See the v4.0.0 release notes for an overview of what’s new in 4.0.0. Use lodash-migrate, lodash-codemods, & eslint-plugin-lodash to help migrate pre-4 lodash code to the latest release.

_v4.17.21

February 21, 2021 — Diff — Docs

Prevent command injection through _.template's variable option
Improve performance of toNumber, trim and trimEnd on large input strings

_v4.17.20

August 14, 2020 — Diff — Docs

Fixed issue with dependencies mapping
Ensured modularized files in the lodash package are up to date

_v4.17.19

July 8, 2020 — Diff — Docs

Allowed _.sortedIndexBy methods to short-circuit for empty arrays
Ensured _.orderBy accepts iteratee path arrays
Ensured _.isEqual returns accurate results without depending on parameter order for circular references
Sanitized sourceURL in _.template
Fix prototype pollution bug in _.zipObjectDeep
Note: releases of 4.17.16 to 4.17.18 of the lodash npm package were corrupted; please update to more recent versions

_v4.17.15

July 17, 2019 — Diff — Docs

Removed unintentionally published project helper scripts

_v4.17.14

July 10, 2019 — Diff — Docs

Reverted use of the "type" field in package.json of lodash-es

_v4.17.13

July 9, 2019 — Diff — Docs

Fixed missing dependency of _createRound

_v4.17.12

July 9, 2019 — Diff — Docs

Ensured _.ceil, _.floor, & _round handle Infinity consistently
Ensured _.debounce clears old timers before starting new ones
Ensured _.mergeWith always provides a stack to customizer
Ensured additions to Object.prototype don’t break lodash initialization
Ensured map and set clones contain custom properties of source values
Fixed prototype pollution for _.defaultsDeep
Fixed prototype pollution for _.template options

_v4.17.11

Sep. 12, 2018 — Diff — Docs

Ensured _.merge handles function properties consistently regardless of number of sources
Ensured Object.prototype is not augmented by _.merge
Ensured placeholder properties are set on fp.convert() results
Avoided ReDoS issue in _.words implementation

_v4.17.10

Apr. 24, 2018 — Diff — Docs

Updated Lodash for better Node.js 10 support

_v4.17.5

Feb. 3, 2018 — Diff — Docs

Ensured _.clone supports subclassed arrays
Ensured _.cloneDeep works with cyclical maps & sets
Ensured _.defaults avoids unnecessary source property access
Ensured _.invert doesn’t error on inverted values without toString methods
Ensured _.merge & _.mergeWith avoid augmenting __proto__ properties
Ensured _.set supports paths with symbols
Ensured _.words detects ordinals in compound words
Ensured fp.update works with paths that refer to functions

_v4.17.4

Dec. 31, 2016 — Diff — Docs

Ensured _.omit with deep paths doesn’t mutate object

_v4.17.3

Dec. 24, 2016 — Diff — Docs

Added support for symbol properties to _.isEqual
Ensured getSymbols helper only gets enumerable symbols
Ensured _.startsWith avoids coercing position of undefined
Flipped iteratee arguments for fp.reduceRight
Removed the array length limit for lazy evaluation

_v4.17.2

Nov. 15, 2016 — Diff — Docs

Ensured _.pick picks keys over paths
Ensured _.spread doesn’t include arguments after those spread
Fixed _.omit performance regression

_v4.17.1

Nov. 14, 2016 — Diff — Docs

Ensured _.omit copies shallow path values by reference
Ensured _.pick supports path arrays
Ensured _.pickBy doesn’t treat keys with dots or brackets as deep paths

_v4.17.0

Nov. 13, 2016 — Diff — Docs

Added deep path support to _.omit & _.pick
Ensured fp.assignAllWith & fp.mergeAllWith accept more than two sources
Made process.binding detection more cautious to avoid chatty debugging

_v4.16.6

Oct. 31, 2016 — Diff — Docs

Ensured _.xor returns an empty array when comparing the same array

_v4.16.5

Oct. 30, 2016 — Diff — Docs

< 10000 ul>

Added support for ordinal numbers to _.words

Ensured _.xor works with more than two arrays

Ensuredfp.convert handles aliased & remapped methods

Improved “fp” debugging

Made “isType” methods resistant to toStringTag spoofing

Made _.isEmpty exit early for nullish values

Refined _.isError checks to avoid false positives for plain objects

Simplified _.isElement

_v4.16.4

Oct. 6, 2016 — Diff — Docs

Added support for buffers to _.transform
Added support for typed arrays to _.isEmpty
Ensured _.toString works on an array of symbols
Fixed _.merge regression with buffers
Normalized buffers & typed arrays keys in “keys” methods
Split _.isArguments out for older & newer environments

_v4.16.3

Oct. 3, 2016 — Diff — Docs

Added a _.runInContext check in the “fp” browser build
Ensured _.defaultsDeep & _.merge consistently assign undefined values
Fixed _.isFunction detection of Proxy in Safari 10
Made _.isEqual treat buffers differently than Uint8Array values
Removed es-sham requirement for older browsers

_v4.16.2

Sept. 25, 2016 — Diff — Docs

Fixed _.sampleSize performance regression
Made “clone” methods use newer Buffer APIs when available

_v4.16.1

Sept. 20, 2016 — Diff — Docs

Fixed backtick removal of _.escape & _.unescape
Improved parse time by 2x in V8

_v4.16.0

Sept. 19, 2016 — Diff — Docs

Added fp.rangeStep & fp.rangeStepRight
Added a cache limit to internal _.memoize use
Avoided V8 de-opts in _.isElement, _.isObject, & _.isObjectLike
Dropped backtick encoding from _.escape & _.unescape
Dropped testing in Node.js 0.10 & 0.12
Ensured __proto__ is treated as a regular key in assignments
Fixed _.bind & _.partial performance regression
Optimized _.concat

_v4.15.0

Aug. 12, 2016 — Diff — Docs

Added Latin Extended-A block support to _.deburr
Reduced dependencies of _.isEmpty & _.toNumber

_v4.14.2

Aug. 8, 2016 — Diff — Docs

Ensured methods work with mocked Date.now, clearTimeout, & setTimeout
Ensured paths of “set” methods overwrite primitives
Ensured fp.nthArg returns a curried function
Reduced dependencies of _.initial, _.merge, & _.tail
Removed old JIT & engine bug guards

_v4.14.1

July 29, 2016 — Diff — Docs

Ensured paths with consecutive empty brackets or dots are parsed correctly
Ensured _.random & “range” methods coerce arguments to finite numbers
Fixed circular reference detection in _.cloneDeep
Removed global prerequisite for exports detection

_v4.14.0

July 24, 2016 — Diff — Docs

Added _.conformsTo & _.defaultTo
Added more “fp” aliases
Added “All” variants of fp/assign, fp/defaults,fp/merge, & fp/zip methods
Ensured debounced cancel uses clearTimeout
Ensured the alias _.first supports shortcut fusion
Ensured _.assignWith respects customizer results of undefined
Ensured _.divide & _.multiply return 1 when no arguments are specified
Ensured _.isEqual has transitive equivalence for circular references
Fixed argument order of fp/zipObjectDeep
Simplified resolving the global object
Stopped unconditional global exports in the browser
Made per method packages zero-dependency modules
Made wrapped function toString results more debuggable
Made “flatten” methods honor Symbol.isConcatSpreadable
Made _.isEqual treat invalid dates as equivalent
Made LARGE_ARRAY_SIZE check in stackSet align with others
Optimized adding values to stacks by not inspecting all key-value pairs
Optimized “isType” methods to use faster Node.js C++ helpers when available
Optimized _.endsWith, _.negate, & _.startsWith

_v4.13.1

May 23, 2016 — Diff — Docs

Ensured _.find & _.findLast provide the correct key param when iterating objects

_v4.13.0

May 22, 2016 — Diff — Docs

Added _.stubArray, _.stubFalse, _.stubObject, _.stubString, & _.stubTrue
Added fromIndex param to _.find, _.findIndex, _.findLast, & _.findLastIndex
Ensured empty brackets & dots in paths are treated as empty property names
Ensured _.pullAll works with the same value for array & values
Ensured _.round works with large precision values
Ensured _.throttle works with a system time of 0
Made _.isNative throw if core-js is detected
Simplified UMD exports
Added fp/findFrom, fp/findIndexFrom, fp/findLastFrom, fp/findLastIndexFrom, fp/indexOfFrom, & fp/lastIndexOfFrom
Fixed argument order of fp/differenceBy, fp/differenceWith, fp/intersectionBy, fp/intersectionWith, fp/without, fp/unionBy, fp/unionWith, fp/xorBy, & fp/xorWith

_v4.12.0

May 8, 2016 — Diff — Docs

Added _.toFinite
Added iteratee arity hints to “forEach” methods
Added support for maps & sets to _.toPairs & _.toPairsIn
Ensured _.merge doesn’t skip trailing function sources
Ensured fp/forEach, fp/forIn, & fp/forOwn cap their iteratee arguments
Ensured fp/update does not convert end of path to an object
Ensured matches methods match arrays with duplicate values
Optimized “flatten” methods
Simplified _.concat
Updated cache implementations

_v4.11.2

Apr. 21, 2016 — Diff — Docs

Ensured _.pullAt correctly sorts indexes greater than 9
Ensured _.words doesn’t treat punctuation as words
Ensured -0 works as path arguments
Ensured set methods like _.uniq & _.xor convert -0 to 0

_v4.11.1

Apr. 14, 2016 — Diff — Docs

Added fp/pluck as an alias of fp/map
Ensured _.debounce defers invoking func when leading is false & wait is 0

_v4.11.0

Apr. 13, 2016 — Diff — Docs

Added _.nth
Added _.matchesProperty shorthand support to _.sortBy
Added support for contractions to case methods & _.words
Avoided unnecessary array cloning in createRecurryWrapper & mergeData
Ensured fp/over doesn’t cap its iteratee arguments
Made _.head avoid accessing array when its length is 0

_v4.10.0

Apr. 11, 2016 — Diff — Docs

Added isIterateeCall check to _.split
Added fp/paths & fp/props as aliases of fp/at
Added fp/propEq as an alias of fp/matchesProperty
Ensured _.debounce queues a trailing call for subsequent debounced calls after maxWait
Ensured _.split handles a limit of 0 correctly in Node.js v0.10
Optimized handling of emojis in string methods
Removed fp/mapObj & fp/propOf aliases

_v4.9.0

Apr. 8, 2016 — Diff — Docs

Added back _.matchesProperty shorthand support to “over” methods
Ensured _.split works with emojis
Fixed malformed fp/toString & fp/valueOf modules

_v4.8.2

Apr. 4, 2016 — Diff — Docs

Reverted _.matchesProperty shorthand support for “over” methods

_v4.8.1

Apr. 4, 2016 — Diff — Docs

Fixed typo in fp/_falseOptions

_v4.8.0

Apr. 4, 2016 — Diff — Docs

Added fp/placeholder module & fp/__ alias
Added convert to unconverted “fp” methods
Added _.matchesProperty shorthand support to “over” methods
Avoided errors in older Firefoxes when coercing Promise to a string
Ensured _.has returns false for nested nullish object values
Ensured _.has treats nested sparse arrays consistently
Fixed argument order of fp/overArgs
Made _.chunk, _.repeat, & _.sampleSize default n to 1 instead of 0
Optimized _.matchesProperty shorthand

_v4.7.0

Mar. 31, 2016 — Diff — Docs

Added _.divide, _.flatMapDeep, _.flatMapDepth, _.meanBy, & _.multiply
Added fp/convert, fp/invokeArgs, fp/invokeArgsMap, fp/padChars, fp/padCharsEnd, fp/padCharsStart, fp/restFrom, & fp/spreadFrom
Added _.entries as an alias of _.toPairs
Added _.entriesIn as an alias of _.toPairsIn
Added several “fp” aliases
Added support for buffers to _.isEmpty
Added support for maps & sets to _.isEmpty & _.size
Added support for deep cloning data views, maps, & sets
Added symbol support to _.omit, _.toNumber, & _.toPath
Avoided a JIT bug in Safari 9 for baseIteratee
Ensured array sequence methods don’t error for falsey values
Ensured _.concat casts non-array array values to arrays
Ensured _.has returns false for nested inherited properties
Ensured _.isEqual compares promises by reference
Ensured _.isPlainObject returns false for objects with a custom [[Prototype]]
Ensured _.mergeWith sources are cloned when customizer returns undefined
Ensured _.startCase only uppercases the first character of each word
Ensured _.words detects words where an all caps word is next to a capitalized word
Fixed argument order of fp/bind, fp/bindKey, & fp/isEqualWith
Fixed aliases fp/all, fp/any, & fp/anyPass
Made _.result resolve values of functions as it deep crawls over them
Memoized stringToPath
Optimized _.pad, _.padEnd, _.padStart, & _.toNumber
Refactored _.debounce to simplify, reduce timers, & fix bugs

_v4.6.1

Mar. 1, 2016 — Diff — Docs

Optimized baseClone to avoid cloning symbols for internal use

_v4.6.0

Feb. 29, 2016 — Diff — Docs

Added _.pullAllWith, _.update, & _.updateWith
Added core.min.js & lodash.min.js to the “fp” module ignored list
Ensured _.defaultsDeep does not overwrite regexp values
Ensured _.isEqual works with maps & sets with circular references
Ensured “fp” uses lodash as the default placeholder
Ensured stack is popped after a recursive merge so that it doesn’t affect sibling properties
Fixed order of arguments in “fp” docs
Optimized baseIsEqualDeep by removing a typed array check & unnecessary stack creation
Optimized _.assign, _.assignIn, & _.intersection
Optimized _.merge to avoid deep cloning sources if a customizer is provided
Removed dead code from getNative
Replaced Symbol checks with Symbol methods checks

_v4.5.1

Feb. 21, 2016 — Diff — Docs

Added core.min.js & lodash.min.js to the npm package
Ensured placeholders persist through more than one curried call
Ensured assignValue assigns values if they aren’t the same own value
Ensured “fp” methods avoid unnecessary cloning
Ensured fp/omitBy & fp/pickBy provide value & key params to iteratees
Fixed arity of fp/orderBy
Used getPrototypeOf to set inheritance when constructor is a function

_v4.5.0

Feb. 17, 2016 — Diff — Docs

Enabled support for cloning expando properties of boolean, number, & string objects
Ensured fp/convert wrappers support iteratee shorthands

_v4.4.0

Feb. 15, 2016 — Diff — Docs

Added _.castArray & _.flattenDepth
Fixed argument order of fp/inRange & fp/zipWith
Enabled fp/convert to auto wrap lodash in the browser
Enabled fp/convert to work when given lodash with options
Ensured fp/convert options works when applied individually
Ensured fp/convert works with category modules
Ensured _.isError 10000 works with subclassed values
Ensured _.merge deep clones array, typed-array, & plain-object sources
Ensured a debounced maxWait timeout isn’t processed on a leading call when leading is false & there isn’t a max delay queued

_v4.3.0

Feb. 7, 2016 — Diff — Docs

Added _.isArrayBuffer, _.isBuffer, _.isMap, _.isSet, _.isWeakMap, & _.isWeakSet
Added options param to fp/convert
Ensured default placeholder values are set for relevant method modules
Ensured _.add & _.subtract return 0 when no arguments are given
Ensured fp/gt, fp/gte, fp/lt, & fp/lte don’t have rearg applied
Improved accuracy of _.debounce & _.throttle

_v4.2.1

Feb. 3, 2016 — Diff — Docs

Added remap of fp/trim as fp/trimChars for chars param support
Ensured wrapped _.bind, _.curry, & _.partial support placeholders
Ensured fp/_baseConvert uses _.spread for _.partial wrapper
Ensured fp/add & fp/subtract don’t have rearg applied

_v4.2.0

Feb. 2, 2016 — Diff — Docs

Added fp/assoc & fp/assocPath as aliases of fp/set
Added fp/dissoc & fp/dissocPath as aliases of fp/unset
Added start param to _.spread
Ensured _.attempt preserves custom errors
Ensured fp/partial & fp/partialRight accept an args param
Ensured fp/unset is immutable
Ensured _.iteratee clones sources for _.matchesProperty shorthand
Made _.flatMap a “Collection” method
Removed global references from the npm package

_v4.1.0

Jan. 29, 2016 — Diff — Docs

Added _.invertBy & _.zipObjectDeep
Added cherry pickable “fp” method modules to the npm package
Ensured fp/convert works with aliases
Ensured _.clone & _.cloneDeep work on prototype objects
Ensured _.mergeWith overwrites primitives with source object clones
Ensured _.sum & _.sumBy return 0 for empty arrays
Optimized _.isEmpty for objects
Fixed argument order of fp/assign, fp/defaults, & fp/merge

_v4.0.1

Jan. 25, 2016 — Diff — Docs

Added _.matches to the core build
Added placeholder support to “fp” methods
Added support for keycap emojis
Ensured _.concat returns an empty array for nullish values
Ensured _.each & _.eachRight aliases have the correct chain behavior
Ensured _.defaultsDeep doesn’t convert function properties to objects
Ensured _.fromPairs can consume results of _.toPairs
Ensured _.isEqual compares objects unordered
Ensured _.noConflict restores _ only if lodash is the current value
Ensured _.words captures all-caps words
Ensured _.words treats all-lower & all-upper postfixes as separate words
Fixed “fp” mapping of several methods
Made _.omitBy & _.pickBy provide a key param to iteratees

_v4.0.0

Jan. 12, 2016 — Diff — Docs

Compatibility Warnings

Removed Bower & Component package support in favor of npm
Dropped IE 6-8 support

Use es5-shim, & optionally es6-shim, to enable support

Made _#times, _#forEach, _#forIn, _#forOwn, & their right-forms implicitly end chain sequences

var wrapped = _([1, 2, 3]);

// in 3.10.1
wrapped.forEach(function(n) { console.log(n); });
// ➜ returns the lodash wrapper without logging until `value` is called
wrapped.forEach(function(n) { console.log(n); }).value();
// ➜ logs each value from left to right and returns the array

// in 4.0.0
wrapped.forEach(function(n) { console.log(n); });
// ➜ logs each value from left to right and returns the array

Removed category names from module paths

 // in 3.10.1
 var chunk = require('lodash/array/chunk');

 // in 4.0.0
 var chunk = require('lodash/chunk');

Removed _.pluck in favor of _.map with iteratee shorthand

var objects = [{ 'a': 1 }, { 'a': 2 }];

// in 3.10.1
_.pluck(objects, 'a'); // ➜ [1, 2]
_.map(objects, 'a'); // ➜ [1, 2]

// in 4.0.0
_.map(objects, 'a'); // ➜ [1, 2]

Removed thisArg params from most methods because they were largely unused, complicated implementations, & can be tackled with _.bind, Function#bind, or arrow functions

 var objects = [{ 'a': 1 }, { 'a': 2 }];
 var context = { 'b': 5 };

 function callback(item) {
   return item.a + this.b;
 }

 // in 3.10.1
 _.map(objects, callback, context);

 // in 4.0.0
 _.map(objects, _.bind(callback, context));

Split _.max & _.min into _.maxBy & _.minBy

var array = [1, 2, 3],
    objects = [{ 'a': 1 }, { 'a': 2 }];

// in 3.10.1
_.max(array); // ➜ 3
_.max(objects, 'a'); // ➜ { 'a': 2 }

_.min(array); // ➜ 1
_.min(objects, 'a'); // ➜ { 'a': 1 }

// in 4.0.0
_.max(array); // ➜ 3
_.maxBy(objects, 'a'); // ➜ { 'a': 2 }

_.min(array); // ➜ 1
_.minBy(objects, 'a'); // ➜ { 'a': 1 }

Method removals
- Removed _.support
- Removed _.findWhere in favor of _.find with iteratee shorthand
- Removed _.where in favor of _.filter with iteratee shorthand
- Removed _.pluck in favor of _.map with iteratee shorthand
Method renames
- Renamed _.first to _.head
- Renamed _.indexBy to _.keyBy
- Renamed _.invoke to _.invokeMap
- Renamed _.modArgs to _.overArgs
- Renamed _.padLeft & _.padRight to _.padStart & _.padEnd
- Renamed _.pairs to _.toPairs
- Renamed _.rest to _.tail
- Renamed _.restParam to _.rest
- Renamed _.sortByOrder to _.orderBy
- Renamed _.trimLeft & _.trimRight to _.trimStart & _.trimEnd
- Renamed _.trunc to _.truncate
Split out methods
- Split _.assign & _.assignIn into _.assignWith & _.assignInWith
- Split _.clone & _.cloneDeep into _.cloneWith & _.cloneDeepWith
- Split _.indexOf & _.lastIndexOf into _.sortedIndexOf & _.sortedLastIndexOf
- Split _.invert into _.invertBy (see v4.1.0)
- Split _.isEqual into _.isEqualWith
- Split _.isMatch into _.isMatchWith
- Split _.max & _.min into _.maxBy & _.minBy
- Split _.merge into _.mergeWith
- Split _.omit & _.pick into _.omitBy & _.pickBy
- Split _.sample into _.sampleSize
- Split _.sortedIndex into _.sortedIndexBy
- Split _.sortedLastIndex into _.sortedLastIndexBy
- Split _.sum into _.sumBy
- Split _.uniq into _.sortedUniq, _.sortedUniqBy, & _.uniqBy
- Split _.zipObject into _.fromPairs
Absorbed _.sortByAll into _.sortBy
Changed the category of _.at to “Object”
Changed the category of _.bindAll to “Util”
Changed _.matchesProperty shorthand to an array of [path, srcValue]
Enabled _.merge to assign undefined if the destination property doesn’t exist
Made “By” methods like _.groupBy & _.sortBy provide a single param to iteratees
Made _.add, _.max, _.min, & _.sum no longer coerce values to numbers
Made _.capitalize uppercase the first character & lowercase the rest (see _.upperFirst)
Made _.eq its own method instead of an alias for _.isEqual
Made _.functions return only own method names
Made _.max & _.min return undefined when passed an empty array
Made _.words chainable by default
Moved ./lodash.js to ./dist/lodash.js in the master branch
Moved ./index.js to ./lodash.js in the npm branch
Removed isDeep params from _.clone & _.flatten
Removed multiValue param from _.invert
Removed support for binding all methods by default from _.bindAll
Removed func-first param signature from _.before & _.after

Low Risk Compatibility Warnings

Dropped boolean options param support in _.debounce, _.mixin, & _.throttle
Dropped support for boolean orders param in _.orderBy
Made _.escapeRegExp align to the defunct ES7 proposal
Made _.max, _.min, & _.sum support arrays only
Removed legacy options param signature from _.template

Notable Changes

Core build
- 4 kB (gzipped) core build (64 methods; Backbone ≥ v1.3.0 compatible)
  _.assignIn, _.before, _.bind, _.chain, _.clone, _.compact, _.concat, _.create, _.defaults, _.defer, _.delay, _.each, _.escape, _.every, _.filter, _.find, _.first, _.flatten, _.flattenDeep, _.forEach, _.has, _.head, _.identity, _.indexOf, _.isArguments, _.isArray, _.isBoolean, _.isDate, _.isEmpty, _.isEqual, _.isFinite, _.isFunction, _.isNaN, _.isNull, _.isNumber, _.isObject, _.isRegExp, _.isString, _.isUndefined, _.iteratee, _.keys, _.last, _.map, _.matches, _max, _.min, _.mixin, _.negate, _.noConflict, _.noop, _.once, _.pick, _.reduce, _.result, _.size, _.slice, _.some, _.sortBy, _.tap, _.thru, _.toArray, _.uniqueId, _#value, & _.values
- Reduced functionality:
  - Cloning only supports arrays & Object objects
  - Iteratee shorthand for _.matchesProperty is removed
  - Lazy evaluation is removed
  - Placeholder support is removed
  - Support for deep property paths is removed
  - Support for maps, sets, & typed arrays is removed
Added 80 methods
- 22 array methods:
  _.concat, _.differenceBy, _.differenceWith, _.fromPairs, _.intersectionBy, _.intersectionWith, _.join, _.pullAll, _.pullAllBy, _.reverse, _.sortedIndexBy, _.sortedIndexOf, _.sortedLastIndexBy, _.sortedLastIndexOf, _.sortedUniq, _.sortedUniqBy, _.unionBy, _.unionWith, _.uniqBy, _.uniqWith, _.xorBy, & _.xorWith
- 18 lang methods:
  _.cloneDeepWith, _.cloneWith, _.eq, _.isArrayLike, _.isArrayLikeObject, _.isEqualWith, _.isInteger, _.isLength, _.isMatchWith, _.isNil, _.isObjectLike, _.isSafeInteger, _.isSymbol, _.toInteger, _.toLength, _.toNumber, _.toSafeInteger, & _.toString
- 13 object methods:
  _.assignIn, _.assignInWith, _.assignWith, _.functionsIn, _.hasIn, _.invoke, _.mergeWith, _.omitBy, _.pickBy, _.setWith, _.toPairs, _.toPairsIn, & _.unset
- 8 string methods:
  _.lowerCase, _.lowerFirst, _.replace, _.split, _.upperCase, _.upperFirst, _.toLower, & _.toUpper
- 8 utility methods:
  _.cond, _.conforms, _.nthArg, _.over, _.overEvery, _.overSome, _.rangeRight, & _.toPath
- 4 math methods:
  _.maxBy, _.mean, _.minBy, & _.sumBy
- 2 collection methods:
  _.flatMap (see v4.2.0) & _.sampleSize
- 2 function methods:
  _.flip & _.unary
- 2 number methods:
  _.clamp & _.subtract
- 1 chain method:
  _#next
Added 3 aliases
- Added _.extend as an alias of _.assignIn
- Added _.extendWith as an alias of _.assignInWith
- Added _.first as an alias of _.head
Removed 17 aliases
- Removed _.all in favor of _.every
- Removed _.any in favor of _.some
- Removed _.backflow in favor of _.flowRight
- Removed _.callback in favor of _.iteratee
- Removed _.collect in favor of _.map
- Removed _.compose in favor of _.flowRight
- Removed _.contains in favor of _.includes
- Removed _.detect in favor of _.find
- Removed _.foldl in favor of _.reduce
- Removed _.foldr in favor of _.reduceRight
- Removed _.include in favor of _.includes
- Removed _.inject in favor of _.reduce
- Removed _.methods in favor of _.functions
- Removed _.object in favor of _.fromPairs or _.zipObject
- Removed _#run in favor of _#value
- Removed _.select in favor of _.filter
- Removed _.unique in favor of _.uniq instead
Performance improvements
- Enabled shortcut fusion for _.at, _.find & _.findLast
- Optimized match methods to avoid deep crawling if object & source identical
- Optimized circular reference searches
- Optimized _.isEqual to avoid stack crawls when arrays or objects are different sizes
Emoji support
- Added support for astral symbols, combining diacritical marks, dingbats, regional indicator symbols, unicode modifiers, variation selectors, & zero-width-joiners to string methods
Functional goodies
- Added _.cond, _.conforms, _.flip, _.nthArg, _.over, _.overEvery, _.overSome, & _.unary
- Moved lodash-fp into lodash as require('lodash/fp') for immutable auto-curried iteratee-first data-last methods

Other Changes

Added clear method to _.memoize.Cache
Added flush method to debounced & throttled functions
Added support for maps, sets, & symbols to _.clone, _.isEqual, & _.toArray
Added support for array buffers to _.isEqual
Added support for converting iterators to _.toArray
Added support for deep paths to _.zipObject
Changed UMD to export to window or self when available regardless of other exports
Enabled _.flow & _.flowRight to accept an array of functions
Ensured “Collection” methods treat functions as objects
Ensured debounce cancel clears args & thisArg references
Ensured _.add & _.sum don’t skip NaN values
Ensured _.assign, _.defaults, & _.merge coerce object values to objects
Ensured _.bindKey bound functions call object[key] when called with the new operator
Ensured _.clone treats generators like functions
Ensured _.clone produces clones with the source’s [[Prototype]]
Ensured _.defaults assigns properties that shadow Object.prototype
Ensured _.defaultsDeep doesn’t merge a string into an array
Ensured _.defaultsDeep & _.merge don’t modify sources
Ensured _.defaultsDeep works with circular references
Ensured _.isFunction returns true for generator functions
Ensured _.keys skips “length” on strict mode arguments objects in Safari 9
Ensured _.merge assigns typed arrays directly
Ensured _.merge doesn’t convert strings to arrays
Ensured _.merge merges plain-objects onto non plain-objects
Ensured _#plant resets iterator data of cloned sequences
Ensured _.random swaps min & max if min is greater than max
Ensured _.range preserves the sign of start of -0
Ensured _.reduce & _.reduceRight use getIteratee in their array branch
Fixed rounding issue with the precision param of _.floor
Made _(...) an iterator & iterable
Made _.drop, _.take, & right forms coerce n of undefined to 0

_v3.10.1

Aug. 4, 2015 — Diff — Docs

Ensured func is a function before calling getData
Ensured _.clone provides the correct number of arguments to customizer
Ensured _#reverse doesn’t modify the original array when called after _#slice

_v3.10.0

June 30, 2015 — Diff — Docs

Added _.ceil, _.defaultsDeep, _.floor, _.modArgs, & _.round
Ensured _.bind works with all built-in constructors
Ensured _#concat treats sparse arrays as dense
Ensured _.chunk floors size values
Ensured _.debounce & _.throttle reset lastCall after cancelling
Ensure _.flow & _.flowRight work with functions combined with _.first
Ensured _.indexOf returns -1 for unmatched binary searches
Ensured _.noConflict operates on root & not context
Made _.escapeRegExp more robust
Made _.sortByOrder support orders of “asc” & “desc”
Optimized _.flatten, _.max, & _.min
Removed fallbacks for _.isArguments, _.isFunction, & _.isPlainObject
Simplified lazy evaluation support
Simplified _.isElement, _.isFinite, _.isNative, _.now, _.parseInt, & _.sum

_v3.9.3

May 26, 2015 — Diff — Docs

Made parseFloat assigned from the context param of _.runInContext
Ensured _.set handles non-index property names that start with numbers correctly

_v3.9.2

May 24, 2015 — Diff — Docs

Made isLaziable work with wrapped lodash methods
Optimized an early exit case in _.isEqual
Optimized _.sample

_v3.9.0

May 19, 2015 — Diff — Docs

Added _.gt, _.gte, _.lt, & _.lte
Added support for an ImmutableMap to _.memoize.Cache
Avoided using require in source comments to improve browserify build times
Ensured baseCreate works in ExtendScript
Ensured customizer results are respected by _.isEqual
Ensured LodashWrapper.prototype.thru exists before creating a wrapper in flow
Ensured _.bind works with ES2015 class constructors
Ensured _.get can return null values
Ensured _.intersection works with a single array
Ensured _.has treats sparse arrays as dense
Ensured _.merge skips undefined array values if a destination value exists
Made null sort behind undefined & NaN
Made _.eq an alias of _.isEqual
Optimized object comparisons in _.isEqual
Optimized _.max & _.min when invoked with iteratees
Optimized _.pullAt & _.remove
Used hasOwnProperty for the creation of reIsNative to avoid issues with core-js

_v3.8.0

May 1, 2015 — Diff — Docs

Added _.mapKeys, _.unzipWith, & _.zipWith
Made _.difference, _.intersection, _.uniq, & _.xor accept array-like values
Ensured empty brackets are ignored by _.get & _.set
Ensured baseAt, basePullAt, & pullAt handle nullish values
Ensured baseGet only returns undefined for incomplete paths
Ensured _.padLeft & _.padRight handle empty strings correctly
Made _.isEqual treat -0 & 0 as equivalent
Narrowed bitmask checks in _.flow & _.flowRight
Optimized lazy slice for start of 0
Optimized “flatten” methods
Restricted Object.assign use to strict mode only

_v3.7.0

Apr. 15, 2015 — Diff — Docs

Added _.get, _.method, _.methodOf, & _.set
Avoided a JIT bug in Safari on at least iOS 8.1-8.3 ARM64
Ensured _.intersection of a single array returns an empty array
Ensured _.remove mutates array after the predicate pass
Ensured methods like _.has & _.get can access index values of strings
Made createAssigner & _.sortByAll use _.restParam
Made _.add coerce augend & addend params to numbers
Made _.assign use built-in Object.assign when available
Made _.inRange swap start & end params when start is greater than end
Added deep path support to methods like _.has, _.get, _.callback, _.invoke, _.matchesProperty, _.method, _.methodOf, _.property, _.propertyOf, _.result, & _.set

_v3.6.0

Mar. 25, 2015 — Diff — Docs

Added _.restParam
Added isIterateeCall guards to _.every, _.includes, & _.some
Added support for iteratee & thisArg params to _.sum
Added support for shortcut fusion optimizations to _.flow & _.flowRight
Ensured lodash bundled by r.js runs in a web worker
Ensured _.deburr removes combining diacritical marks
Ensured _.difference is based on the values of the first param only
Expanded metadata optimizations to more combinations of curried functions
Made _.matches work with non-plain objects & match inherited properties
Optimized _.findLast, _.reduce, & _.reduceRight
Reduced code duplication with internal method creator functions

_v3.5.0

Mar. 8, 2015 — Diff — Docs

Added string replace & split chaining methods
Ensured lazy drop works when applied after filter
Optimized curried method performance

_v3.4.0

Mar. 6, 2015 — Diff — Docs

Added _.add, _.sortByOrder, & _.sum
Adjusted root to work when bundled by webpack & running in a web worker
Ensured lazy chaining works with combinations of drop & dropWhile
Ensured _.defaults works as an iteratee for _.reduce
Reduced side effects of shortcut fusion
Optimized baseFlatten, baseIndexOf, indexOfNaN, _.flow, & _.flowRight
Optimized lazy evaluation for iteratees with one param

_v3.3.1

Feb. 24, 2015 — Diff — Docs

Ensured lazy takeWhile works with lazy reverse & last
Ensured wait defaults to 0 for _.debounce & _.throttle
Ensured isIterateeCall doesn’t error if index is missing a toString method
Optimized _.difference, _.intersection, & _.uniq in Firefox

_v3.3.0

Feb. 20, 2015 — Diff — Docs

Added _.inRange
Added links to each method’s npm package to the documentation
Enabled _.clone to work with more truthy isDeep values
Ensured each lodash wrapper module sets up their inheritance
Ensured isIterateeCall works with NaN values
Ensured _.merge avoids iterating string object or source params
Optimized _.attempt
Reduced nested dependencies of _.template

_v3.2.0

Feb. 12, 2015 — Diff — Docs

Added _.fill, _.matchesProperty, & _.spread
Added _#commit & _#plant
Added support for lazy _.compact & _.toArray
Enabled _.attempt to provide additional arguments to func
Ensured _.flow returns an identity function when called without arguments
Ensured _#reverse tracks __chain__ values
Ensured lazy _.slice handles floating-point start & end params
Fixed lazy _.slice when used after _.filter
Made _#run an alias of _#value

_v3.1.0

Feb. 3, 2015 — Diff — Docs

Added _.startCase
Ensured isIterateeCall works correctly with objects

_v3.0.1

Jan. 30, 2015 — Diff — Docs

Ensured _.slice coerces floating-point start & end params to integers
Fixed lazy initial, rest, & reverse
Fixed _.merge regression with DOM elements

_v3.0.0

Jan. 26, 2015 — Diff — Docs

Compatibility Warnings

Made chaining lazy, that is, execution is deferred until _#value is implicitly or explicitly called

var wrapped = _([1, 2, 3]);

// in 2.4.1
wrapped.forEach(function(n) { console.log(n); });
// ➜ logs each value from left to right and returns the lodash wrapper

// in 3.0.0
wrapped.forEach(function(n) { console.log(n); });
// ➜ returns the lodash wrapper without logging until `value` is called
wrapped.forEach(function(n) { console.log(n); }).value();
// ➜ logs each value from left to right and returns the array

Ensured each segment of a chain sequence may be repeatly applied

var array = [1],
    wrapped = _(array);

// in 2.4.1
var a = wrapped.push(2), // pushes `2` to `array`
    b = wrapped.push(3); // pushes `3` to `array`

a.value(); // ➜ returns `array`; [1, 2, 3]
b.value(); // ➜ returns `array`; [1, 2, 3]

// in 3.0.0
var a = wrapped.push(2), // creates a lazy sequence to push `2` to `array`
    b = wrapped.push(3); // creates a lazy sequence to push `3` to `array`

a.value(); // ➜ pushes `2` to `array` and returns `array`; [1, 2]
b.value(); // ➜ pushes `3` to `array` and returns `array`; [1, 2, 3]
a.value(); // ➜ pushes `2` to `array` and returns `array`; [1, 2, 3, 2]
b.value(); // ➜ pushes `3` to `array` and returns `array`; [1, 2, 3, 2, 3]

// use `_#commit` to commit a sequence and continue chaining
var a = wrapped.push(2).commit(), // pushes `2` to `array`
    b = wrapped.push(3).commit(); // pushes `3` to `array`

a.value(); // ➜ returns `array`; [1, 2, 3]
b.value(); // ➜ returns `array`; [1, 2, 3]

Made _.flatten shallow by default & remove callback support

var array = [1, [[2], 3]],
    objects = [{ 'a': [1] }, { 'a': [2, 3] }];

// in 2.4.1
_.flatten(array); // ➜ [1, 2, 3]
_.flatten(objects, 'a'); // [1, 2, 3]

// in 3.0.0
_.flatten(array); // ➜ [1, [2], 3]
_.flattenDeep(array); // ➜ [1, 2, 3]
_(objects).pluck('a').flatten().value(); // [1, 2, 3]

Removed the data parameter from _.template

var string = '<%= o.a %>',
    options = { 'variable': 'o' },
    data = { 'a': 'b' };

// in 2.4.1
_.template(string, data, options); // ➜ 'b'

// in 3.0.0
_.template(string, options)(data); // ➜ 'b'

Split _.first & _.last into _.take, _.takeWhile, _.takeRight, & _.takeRightWhile

var array = [1, 2, 3],
    lessThanTwo = function(value) { return value < 2; },
    greaterThanTwo = function(value) { return value > 2; };

// in 2.4.1
_.first(array); // ➜ 1
_.first(array, 2); // ➜ [1, 2]
_.first(array, lessThanTwo);   // ➜ [1]

_.last(array); // ➜ 3
_.last(array, 2); // ➜ [2, 3]
_.last(array, greaterThanTwo); // ➜ [3]

// in 3.0.0
_.first(array); // ➜ 1
_.take(array, 2); // ➜ [1, 2]
_.takeWhile(array, lessThanTwo); // ➜ [1]

_.last(array); // ➜ 3
_.takeRight(array, 2); // ➜ [2, 3]
_.takeRightWhile(array, greaterThanTwo); // ➜ [3]

Split _.initial & _.rest into _.dropRight, _.dropRightWhile, _.drop, & _.dropWhile

var array = [1, 2, 3],
    lessThanTwo = function(value) { return value < 2; },
    greaterThanTwo = function(value) { return value > 2; };

// in 2.4.1
_.initial(array); // ➜ [1, 2]
_.initial(array, 2); // ➜ [1]
_.initial(array, greaterThanTwo); // ➜ [1, 2]

_.rest(array); // ➜ [2, 3]
_.rest(array, 2); // ➜ [3]
_.rest(array, lessThanTwo); // ➜ [2, 3]

// in 3.0.0
_.initial(array); // ➜ [1, 2]
_.dropRight(array, 2); // ➜ [1]
_.dropRightWhile(array, greaterThanTwo); // ➜ [1, 2]

_.rest(array); // ➜ [2, 3]
_.drop(array, 2); // ➜ [3]
_.dropWhile(array, lessThanTwo); // ➜ [2, 3]

Aligned _.isFinite & _.keys with ES2015
Changed the category of _.clone & _.cloneDeep, & “isType” methods from “Object” to “Lang”
Changed the category of _.escape, _.template, & _.unescape from “Util” to “String”
Changed the category of _.range from “Array” to “Util”
Changed the category of _.toArray from “Collection” to “Lang”
Made method categories singular
Made “Object” methods coerce primitives to objects
Made _.clone & _.cloneDeep return a new object for unsupported types
Made _.findWhere its own method instead of an alias for _.find
Made _.max & _.min non-chainable by default
Made _.memoize caches have the Map interface of delete, get, has, & set
Made _.unzip its own method instead of an alias for _.zip
Moved ./dist/lodash.js to ./lodash.js in the master branch
Moved ./dist/lodash.js to ./lodash.js in the npm branch
Moved ./dist/lodash.compat.js to the lodash/lodash-compat repository
Moved support for sorting by multiple properties from _.sortBy to _.sortByAll
Removed result sorting from _.functions
Removed the underscore build
Renamed _.createCallback to _.callback
Renamed _.support.argsClass to _.support.argsTag
Renamed _.support.nodeClass to _.support.nodeTag
Restricted _.mixin to iterating only own properties of source objects
Expanded the number of arguments provided to customizer callbacks of _.assign,
_.clone, _.cloneDeep, _.isEqual, & _.merge

Low Risk Compatibility Warnings

Added customizable argument placeholder support to _.bind, _.bindKey, _.curry, _.curryRight, _.partial, & _.partialRight
Added support for matching NaN to _.difference, _.includes, _.indexOf, _.intersection, _.lastIndexOf, _.union, _.uniq, & _.xor
Ensured _.assign & _.merge don’t assign customizer results if it’s unchanged
Ensured _.mixin doesn’t extend lodash when given an empty options object
Ensured _.sortedIndex returns values that align with the sort order of _.sortBy
Ensured functions of _.matches return true when comparing empty sources
Ensured functions of _.matches perform own property checks on objects
Made _.chain use an existing wrapper if available instead of creating a new wrapper
Removed the argCount parameter from _.callback

Notable Changes

Added 47 methods

17 string methods:
_.camelCase, _.capitalize, _.deburr, _.endsWith, _.escapeRegExp, _.kebabCase, _.pad, _.padLeft, _.padRight, _.repeat, _.snakeCase, _.startsWith, _.trim, _.trimLeft, _.trimRight, _.trunc, & _.words
11 array methods:
_.chunk, _.dropRight, _.dropRightWhile, _.dropWhile, _.flattenDeep, _.pullAt, _.slice, _.sortedLastIndex, _.takeRight, _.takeRightWhile, & _.takeWhile
6 function methods:
_.ary, _.before, _.curryRight, _.flow, _.negate, & _.rearg
5 lang methods:
_.isError, _.isMatch, _.isNative, _.isTypedArray, & _.toPlainObject
3 utility methods:
_.attempt, _.matches, & _.propertyOf
2 collection methods:
_.partition & _.sortByAll
2 object methods:
_.keysIn & _.valuesIn
1 chain method:
_.thru

Added 5 aliases

Added _.backflow & _.compose as aliases of _.flowRight
Added _.contains as an alias of _.includes
Added _.iteratee as an alias of _.callback
Added _#toJSON as an alias of _#valueOf

Performance improvements

Improved overall performance 20-40%
Method chaining supports lazy evaluation
Methods with support for shortcut fusion:
_.drop, _.dropRight, _.dropRightWhile, _.dropWhile, _.filter, _.first, _.initial, _.last, _.map, _.pluck, _.reject, _.rest, _.reverse, _.slice, _.take, _.takeRight, _.takeRightWhile, _.takeWhile, & _.where
Other optimized methods:
_.bind, _.clone, _.cloneDeep, _.compact, _.compose, _.contains, _.difference, _.escape, _.flatten, _.invoke, _.isEqual, _.isObject, _.matches, _.max, _.min, _.partial, _.shuffle, _.unescape, _.uniq, _.without, & _.zip

Functional goodies

Added _.ary, _.curryRight, _.flow, & _.rearg
Added placeholder support to _.bind, _.bindKey, _.curry, _.curryRight, _.partial, & _.partialRight
Methods that work as an iteratee for _.map, & the like, out of the box:
_.ary, _.callback, _.chunk, _.clone, _.create, _.curry, _.curryRight, _.drop, _.dropRight, _.flatten, _.invert, _.max, _.min, _.parseInt, _.slice, _.sortBy, _.take, _.takeRight, _.template, _.trim, _.trimLeft, _.trimRight, _.trunc, _.random, _.range, _.sample, _.uniq, & _.words
Methods that work as an iteratee for _.reduce, & the like, out of the box:
_.assign, _.defaults, _.merge, & _.sortAllBy

Other Changes

Added cherry pickable method modules to the npm package
Added cancel method to debounced & throttled functions
Added defaultValue param to _.result
Added multiValue param to _.invert
Added thisArg param to _.tap
Added _.memoize.Cache to enable Map/WeakMap to be used
Added support for cloning array buffers & typed arrays to _.clone & _.cloneDeep
Added support for comparing error objects & typed arrays to _.isEqual
Enabled the sourceURL option of _.template to work in production builds
Ensured _.at, _.matches, & _.pullAt work with falsey values when keys are given
Ensured _.callback doesn’t error when func is nullish & thisArg is given
Ensured _.callback supports binding built-in methods
Ensured _.debounce & _.throttle 8000 work if the system time is set backwards
Ensured _.difference works with arrays regardless of argument position
Ensured _.findWhere & _.where always use _.matches
Ensured _.includes supports fromIndex when iterating objects
Ensured _.indexOf([], undefined, true) returns -1 instead of 0
Ensured _.intersection ignores non-array secondary values
Ensured _.isEqual works with wrapped objects containing constructor properties
Ensured _.keys treats sparse arrays as dense
Ensured _.keys works with string objects in IE < 9
Ensured _.matches comparison isn’t affected by changes to source objects
Ensured _.max & _.min return the correct value when callback computes ±Infinity
Ensured _.merge ignores undefined values of source object properties
Ensured _.partial & _.partialRight work with curried functions
Ensured _.pluck always uses _.property
Ensured _.random returns 1 or 0 when called with no arguments
Ensured _.range, _.slice, & other methods handle NaN arguments
Ensured _.runInContext uses a zeroed _.uniqueId counter
Ensured _.transform checks that object is an object before using its [[Prototype]]
Ensured _.where handles source objects with undefined property values
Ensured _.where only returns elements that contain all source array/object values
Ensured browserified lodash works in web workers
Ensured customizing _.indexOf affects _.includes when iterating objects
Ensured lodash works in NW.js
Ensured lodash doesn’t add Function.prototype extensions to its prototype
Fixed _.isFunction for typed array constructors in Safari 8
Made _.escape & _.unescape handle backticks
Made _.isElement more robust
Made _.parseInt more closely follow spec
Made _.wrap use _.identity when wrapper is nullish
Made templates avoid referencing _.escape if “escape” delimiters are not used
Made array-like object checks follow ES2015 ToLength
Made use of Set in _.difference, _.intersection, & _.uniq
Removed array & object pools
Removed all method compilation from the compat build
Updated the sourceURL syntax used by _.template

_v2.4.2

Apr. 26, 2015 — Diff — Docs

Avoided memory leaks in _.bind, _.bindKey, _.curry, _.partial, & _.partialRight

_v2.4.1

Dec. 2, 2013 — Diff — Docs

Ensured __bindData__ is properly cloned
Ensured _.isEqual can compare cyclical objects with shared property values
Optimized _.partial & _.partialRight
Reached ~100% code coverage

_v2.4.0

Nov. 25, 2013 — Diff — Docs

Added _.constant, _.mapValues, _.now, _.property, & _.xor
Added an options param to _.mixin to specify whether functions added are chainable
Added support for _.sortBy to accept an array of property names to sort by
Enabled _.zipObject to accept an array of keys with no values param
Removed conditional setImmediate use from _.defer

_v2.3.0

Nov. 10, 2013 — Diff — Docs

Added _.create & _.noop
Avoided memory leaks in _.debounce & _.throttle
Enhanced _.createCallback to avoid binding functions bound by Function#bind
Ensured rebound functions correctly partially apply arguments
Ensured _.isEqual works with values from Object.create(null) & _(false)
Ensured _.min & _.max work as callbacks for _.map
Ensured _.template coerces the text param to a string
Optimized _.difference, _.omit, & _.without by way of baseDifference
Optimized _.isBoolean, _.isNumber, & _.isString for the false case
Optimized _.sample & _.shuffle by way of baseRandom
Reduced _.wrap by way of createBound
Removed native Function#bind use for better cross-environment consistency

_v2.2.1

Oct. 3, 2013 — Diff — Docs

Ensured _.mixin creates functions that work with _.chain
Ensured the the createObject fallback is included in the modern build

_v2.2.0

Sept. 28, 2013 — Diff — Docs

Added _.clone support for date, regexp, & other built-in objects
Ensured _.random avoids excessive results of 0 for floating-point numbers
Made compat & underscore builds use Date.now when available
Reduced dependencies on getObject & releaseObject

_v2.1.0

Sept. 22, 2013 — Diff — Docs

Added Object.defineProperty fallback for the modern build
Added support to _.random to explicitly specify floating point numbers
Enabled _.compose to be invoked without arguments
Ensured _.flatten works with extremely large arrays
Ensured _.support properties aren’t minified
Ensured reThis isn’t used in Windows 8 applications
Made UMD more resistant to false positives
Optimized _.isArguments & _.isArray fallbacks

_v2.0.0

Sept. 13, 2013 — Diff — Docs

Compatibility Warnings

Aligned _.after with Underscore 1.5.0, making it always return a function
Made _.unzip an alias of _.zip

Notable Changes

Created lodash methods as npm packages & AMD/Node.js modules
Made _.chain force chaining for all methods
Moved the build utility to lodash-cli
Optimized _.contains, _.debounce, _.isArguments, _.throttle, & _.where
Optimized functions of _.bind, _.bindKey, _.curry, _.partial, & _.partialRight
Added _.curry, _.forEachRight, _.indexBy, _.findLast, _.findLastIndex, _.findLastKey, _.forInRight, _.forOwnRight, _.pull, _.remove, & _.sample

Other Changes

Added Curl & Dojo module loaders to the unit tests
Added the modularize build option
Added support for the iife command to be used without an %output% token
Added support for _.mixin to accept a destination object
Added support for _.range to accept a step of 0
Ensured “Array” methods support arguments objects
Ensured “Function” methods throw on non-functions
Ensured _.at works as a callback for _.map
Ensured _.createCallback works when no argCount is specified
Ensured _.first & _.last return arrays when given an n with a falsey array
Ensured _.flatten works with arguments objects
Ensured minified files work with Dojo’s builder
Ensured _.zipObject skips falsey elements
Improved dead code removal from builds
Improved JSDoc syntax
Made _.eachRight an alias of _.forEachRight
Made _.memoize avoid prefixing cache keys when using a resolver function
Removed local clearTimeout & setTimeout variables from the underscore build
Reduced the size of the repo & npm package
Simplified the bailout in createCache
Updated sourceURL & sourceMappingURL syntax
Updated underscore build compatibility to v1.5.2

_v1.3.1

June 12, 2013 — Diff — Docs

Added missing cache property to the objects returned by getObject
Ensured maxWait unit tests pass in Ringo
Increased the maxPoolSize value
Optimized releaseArray & releaseObject

_v1.3.0

June 11, 2013 — Diff — Docs

Added _.transform
Added _.chain & _.findWhere aliases
Added internal array & object pooling
Added Istanbul test coverage reports to Travis CI
Added maxWait option to _.debounce
Added support for floating point numbers to _.random
Added Volo configuration to package.json
Adjusted UMD for component build
Enabled more stable mixing of lodash & underscore build methods
Ensured debounced function with leading & trailing options works as expected
Ensured minified builds work with the Dojo builder
Ensured minification avoids deoptimizing expressions containing boolean values
Ensured support for --output paths containing build command keywords
Ensured unknown types return false in _.isObject & _.isRegExp
Ensured _.clone, _.flatten, & _.uniq can be used as callback for _.map
Ensured _.forIn works on objects with longer inheritance chains in IE < 9
Ensured _.isPlainObject returns true for empty objects in IE < 9
Ensured _.max & _.min chain correctly
Ensured clearTimeout use doesn’t cause errors in T 57A6 itanium
Ensured that the --stdout build option doesn’t write to a file
Exposed memoized function’s cache
Fixed Error.prototype iteration bugs
Fixed “scripts” paths in component.json
Made methods support customizing _.indexOf
Made the build track dependencies of private functions
Made the template pre-compiler build option avoid escaping non-ascii characters
Made _.createCallback avoid binding functions if they don’t reference this
Optimized the Closure Compiler minification process
Optimized the large array cache for _.difference, _.intersection, & _.uniq
Optimized internal _.flatten & _.indexOf use
Reduced _.unzip & _.zip
Removed special handling of arrays in _.assign & _.defaults

_v1.2.1

Apr. 29, 2013 — Diff — Docs

Added Component package support
Updated the build utility to work with changes in GitHub’s API
Ensured _.isPlainObject works with objects created by Object.create(null)
Ensured “isType” methods return false for subclassed values
Ensured debounced functions, with leading & trailing calls enabled, only perform trailing calls after they’re called more than once

_v1.2.0

Apr. 16, 2013 — Diff — Docs

Added _.unzip
Added an options param to _.debounce & _.throttle
Enabled non-underscore builds to include _.findWhere & _.chain
Ensured “Array” & “Object” methods work with arguments objects & arrays respectively
Ensured build utility runs on Windows
Ensured underscore build versions of “isType” methods align with Underscore
Ensured methods avoid issues with the __proto__ property
Ensured _.isEqual uses a callback only if it’s a function
Ensured _.merge applies a callback to nested properties
Ensured _.merge provides the correct callback arguments when comparing objects
Made lodash work with Browserify
Removed all method compilation from the modern build

_v1.1.1

Mar. 27, 2013 — Diff — Docs

Ensured the underscore build of _.forEach accepts a thisArg param
Updated vendor/tar to work with Node.js v0.10

_v1.1.0

Mar. 26, 2013 — Diff — Docs

Added _.createCallback, _.findIndex, _.findKey, _.parseInt, & _.runInContext
Added _.support
Added callback & thisArg params to _.flatten
Added rhino -require support
Added CommonJS/Node.js support to precompiled templates
Ensured the exports object is not a DOM element
Ensured _.isPlainObject returns false for objects without a [[Class]] of “Object”
Made callback support in _.cloneDeep more closely follow its documentation
Made _.object an alias of _.zipObject
Made the template precompiler create missing directories of --output paths
Optimized method chaining, object iteration, _.find, & _.pluck
Updated backbone build method dependencies

_v1.0.2

Feb. 18, 2013 — Diff — Docs

Ensured _.isPlainObject works when built-in Object.getPrototypeOf is unavailable

_v1.0.1

Feb. 18, 2013 — Diff — Docs

Added support for specifying source map URLs in -p/--source-map options
Ensured the second argument to _.assign is not treated as a callback
Ensured -p/--source-map build options correctly set the sourceMappingURL
Made -p/--source-map set source map “sources” keys based on the build
Made _.defer use setImmediate, in Node.js, when available
Made _.where search arrays for values regardless of their index position
Removed dead code from _.template

_v1.0.0

Feb. 14, 2013 — Diff — Docs

Compatibility Warnings

Made _.defaults preserve null values, instead of overwriting them

Changes

Added _.at & _.partialRight
Added modern & -p/--source-map build options
Added “imports” option to _.templateSettings
Added support for _.pluck & _.where callback shorthands
Ensured _.assign & _.defaults support arrays
Ensured _.merge assigns null values & produces dense arrays
Deferred minifier downloads until the lodash utility requires them
Flipped noNodeClass test to avoid Firebug’s “break on all errors” feature
Made _.where support deep object comparisons
Optimized _.invert, _.pairs, & _.values
Reduced _.max, _.min, _.pluck, _.toArray, & _.where
Removed support for automatic with-statement removal from _.template
Simplified createIterator & iteratorTemplate
Tweaked _.uniqueId to avoid problems with buggy minifiers
Updated underscore build compatibility to v1.4.4
Added callback & thisArg params to _.assign, _.clone, _.cloneDeep, _.first, _.last, _.initial, _.isEqual, _.merge, & _.rest

_v1.0.0-rc.3

Dec. 17, 2012 — Diff — Docs

Compatibility Warnings

Made _#join, _#pop, & _#shift wrapper methods return unwrapped values
Made “Function” methods wrapper counterparts return wrapped values
Removed “chain” methods

Changes

Added _.cloneDeep
Added _.once to the backbone build
Ensured backbone builds implement Underscore’s chaining behavior
Ensured the settings=… build option doesn’t clobber the default moduleId
Ensured lodash’s npm package works when packages aren’t globally installed
Made compiled templates exported for AMD use the lodash module for _
Removed the _.forEach dependency from _.intersection
Optimized _.isArray & _.isFunction fallbacks as well as _.intersection, _.isDate, _.isRegExp, _.reduce, _.reduceRight, _.union, & _.uniq

_v1.0.0-rc.2

Dec. 5, 2012 — Diff — Docs

Specified more method chaining behaviors
Updated underscore build compatibility to v1.4.3

_v1.0.0-rc.1

Dec. 4, 2012 — Diff — Docs

Compatibility Warnings

Added support for arguments objects to _.clone
Ensured _.clone creates plain object clones of non-plain objects
Made _(…) chain automatically without needing to call _#chain
Made _.isEqual equate arguments objects to similar Object objects

Changes

Ensure lodash runs in the JS engine embedded in Adobe products
Ensured _.reduce & _.reduceRight provide the correct callback arguments
Ensured _.throttle nulls the timeoutId
Made deep _.clone more closely follow the structured clone algorithm
Optimized compiled templates in Firefox
Optimized _.forEach, _.forOwn, _.isNumber, & _.isString
Simplified iteratorTemplate

_v0.10.0

Nov. 17, 2012 — Diff — Docs

Compatibility Warnings

Renamed _.lateBind to _.bindKey
Made _.defaults & _.extend iterate only own properties of source objects to align with Object.assign

Changes

Added the build commands used to custom build copyright/license headers
Added _.assign
Ensured the underscore build of _.find returns the first match, not last
Ensured _.defaults, _.extends, & _.merge work with _.reduce
Made lodash’s npm package installation work with more system configurations
Made _.extend an alias of _.assign
Optimized _.contains, _.defaults, _.extend, & _.filter
Restricted _.where to iterate only own properties of source objects
Updated backbone build lodash method dependencies

_v0.9.2

Nov. 9, 2012 — Diff — Docs

Added fromIndex param to _.contains
Added moduleId build option
Added Closure Compiler “simple” optimizations to the build process
Added support for strings in _.max & _.min
Added support for ES2015 template delimiters to _.template
Ensured re-minification of lodash by third parties avoids Closure Compiler bugs
Optimized _.every, _.find, _.some, & _.uniq

_v0.9.1

Oct. 31, 2012 — Diff — Docs

Ensured _.every returns false as soon as the callback result is falsey
Ensured _.isFinite returns false for non-numeric values
Removed _.forEach chainability in the underscore build
Simplified _.union

_v0.9.0

Oct. 24, 2012 — Diff — Docs

Added a sourceURL option to _.template
Ensured _.where returns an empty array if given an empty properties object
Expanded _.isFinite to return true for numeric strings
Reduced _.intersection, _.omit, _.pick, _.sortedIndex, & _.where
Reduced the npm package size by only downloading minifiers for global installs
Reduced lodash’s file size
Improved source code comprehension by removing compilation from _.bindAll, _.contains, _.countBy, _.every, _.filter, _.find, _.functions, _.groupBy, _.invert, _.invoke, _.isEmpty, _.map, _.merge, _.omit, _.pairs, _.pick, _.pluck, _.reduce, _.reject, _.some, _.sortBy, _.values, _.where, & internal shimKeys

_v0.8.2

Oct. 10, 2012 — Diff — Docs

Ensured _.map returns an array when given a falsey collection
Ensured _.throttle clears its timeout when func is called
Made _.max, _.min, _.shuffle support iterating objects
Reduced createIterator, _.clone, _.compact
Re-optimized _.max, _.min, & _.sortedIndex

_v0.8.1

Oct. 4, 2012 — Diff — Docs

Enabled deep clone support in the underscore build when clone is explicitly included
Reverted removal of first argument falsey checks from methods

_v0.8.0

Oct. 1, 2012 — Diff — Docs

Compatibility Warnings

Made _.random return 0 or 1 when no arguments are given
Moved late bind functionality from _.bind to _.lateBind
Removed first argument falsey checks from methods
Removed support for custom clone, isEqual, toArray methods from _.clone, _.isEqual, & _.toArray

Changes

Added -d/--debug, -m/--minify, minus, plus, settings, & template build options
Added _.isPlainObject & _.lateBind
Enabled _.sortedIndex to accept a property name as the callback param
Ensured methods accept a thisArg of null
Fixed the iife build option to accept more values
Made _.times return an array of callback results
Simplified _.max, _.min, & _.reduceRight

_v0.7.0

Sept. 11, 2012 — Diff — Docs

Compatibility Warnings

Renamed _.zipObject to _.object
Replaced _.drop with _.omit
Made _.drop an alias of _.rest

Changes

Added _.invert, _.pairs, & _.random
Added _.result to the backbone build
Added exports, iife, -c/--stdout, -o/--output, & -s/--silent build options
Ensured isPlainObject works with objects from other documents
Ensured _.isEqual compares values with circular references correctly
Ensured _.merge work with four or more arguments
Ensured _.sortBy performs a stable sort for undefined values
Ensured _.template works with “interpolate” delimiters containing ternary operators
Ensured the production build works in Node.js
Ensured template delimiters are tokenized correctly
Made pseudo private properties _chain & _wrapped double-underscored to avoid conflicts
Made minify.js support underscore.js
Reduced the size of mobile & underscore builds
Simplified _.isEqual & _.size

_v0.6.1

Aug. 29, 2012 — Diff — Docs

Ensured IE conditional compilation isn’t enabled by the useSourceURL test
Optimized isPlainObject

_v0.6.0

Aug. 28, 2012 — Diff — Docs

Added callback & thisArg params to _.drop & _.pick
Added hasObjectSpliceBug test to avoid delete operator use
Added _.unescape
Ensured _.reduce works with string objects in IE < 9
Made _.omit an alias of _.drop
Made compiled methods take advantage of engines with strict mode optimizations
Optimized _.intersection & removed its dependency on _.every
Reduced the file size of the underscore build

_v0.5.2

Aug. 21, 2012 — Diff — Docs

Ensured _.isElement uses strict equality for its duck type check
Ensured _.isObject returns a boolean value
Ensured _.template & “Object” methods don’t error when given falsey values
Made _.template generate less unused code in compiled templates

_v0.5.1

Aug. 18, 2012 — Diff — Docs

Ensured _.bind correctly appends array arguments to partially applied arguments in older browsers

_v0.5.0

Aug. 17, 2012 — Diff — Docs

Added _.countBy, _.drop, _.merge, & _.where
Added csp (Content Security Policy) & underscore build options
Added deep cloning support to _.clone
Added Jam package support
Added support for exiting early in _.forEach, _.forIn, & _.forOwn
Added support for jQuery/MooTools DOM query collections to _.isEmpty & _.size
Ensured development build works with IE conditional compilation enabled
Ensured _.clone doesn’t clone arguments objects, DOM nodes, functions, or non-plain objects
Ensured _.filter’s callback can’t modify result values
Ensured _.isEmpty, _.isEquals, & _.size support arguments objects
Ensured _.isEqual doesn’t inspect DOM nodes, works with objects from other documents, & calls custom isEqual methods before checking strict equality
Ensured _.once frees the given function for garbage collection
Ensured _.sortBy performs a stable sort
Ensured reEvaluateDelimiter is used when _.templateSettings.evaluate is undefined
Made _.range coerce arguments to numbers
Optimized _.isFunction

_v0.4.2

July 16, 2012 — Diff — Docs

Added strict build option
Ensured _.bindAll, _.defaults, & _.extend avoid strict mode errors on read-only properties
Optimized the iteration of large arrays in _.difference, _.intersection, & _.without
Fixed build bugs related to removing variables

_v0.4.1

July 11, 2012 — Diff — Docs

Fixed _.template regression
Optimized build process to detect & remove more unused variables

_v0.4.0

July 11, 2012 — Diff — Docs

Added bin & scripts entries to package.json
Added legacy build option
Added cross-browser support for strings to “Collection” methods
Added _.zipObject
Leveraged _.indexOf’s fromIndex in _.difference & _.without
Optimized compiled templates
Optimized inlining the iteratorTemplate for builds
Optimized object iteration for “Collection” methods
Optimized partially applied _.bind in V8
Made compiled templates more debuggable
Made _.size work with falsey values & consistent cross-browser with arguments objects
Moved _.groupBy & _.sortBy back to the “Collection” category
Removed arguments object from _.range

_v0.3.2

June 14, 2012 — Diff — Docs

Ensured _.escape returns an empty string for nullish values
Ensured sourceURL support doesn’t cause errors in Adobe’s JS engine
Fixed regression in generating custom builds
Moved _.invoke & _.pluck back to the “Collection” category
Moved _.tap to the “Seq” category

_v0.3.1

June 10, 2012 — Diff — Docs

Added backbone build option
Ensured “Array” methods allow falsey array params
Removed _.isArguments fallback from the mobile build
Simplified _.pluck, _.values & _(...) method wrappers

_v0.3.0

June 6, 2012 — Diff — Docs

Added _.forIn & _.forOwn
Added category build option
Added fromIndex param to _.indexOf & _.lastIndexOf
Added //@ sourceURL support to _.template
Added thisArg param to _.sortedIndex & _.uniq
Ensured array-like objects with invalid length properties are treated like regular objects
Ensured _.sortedIndex supports arrays with high length values
Fixed prototype iteration bug in _.keys
Optimized _.times & this bindings in iterator methods

_v0.2.2

May 30, 2012 — Diff — Docs

Added mobile build option
Ensured _.find returns undefined for unmatched values
Ensured _.templateSettings.variable is compatible with Underscore
Optimized _.escape
Reduced dependencies of _.find

_v0.2.1

May 24, 2012 — Diff — Docs

Adjusted the lodash export order for r.js
Ensured _.groupBy values are added to own, not inherited, properties
Made _.bind follow ES5 spec to support a popular Backbone.js pattern
Removed the alias _.intersect
Simplified _.bind, _.flatten, _.groupBy, _.max, & _.min

_v0.2.0

May 21, 2012 — Diff — Docs

Added _.partial
Added thisArg param to _.groupBy
Added “lazy bind” support to _.bind
Added custom build options
Added default _.templateSettings.variable value
Added native method overwrite detection to avoid bad native shims
Added support for more AMD build optimizers & aliasing as the “underscore” module
Added whitespace to compiled strings
Commented the iterationFactory options object
Ensured _(...) returns given wrapper instances
Ensured _.max & _.min support extremely large arrays
Ensured _.throttle works in tight loops
Fixed clearTimeout typo
Fixed [DontEnum] bug in IE < 9
Fixed prototype iteration bug in Firefox < 3.6, Opera < 11.60, & Safari < 5.1
Inlined _.isFunction calls
Made _.debounce’ed functions match _.throttle’ed functions’ return value behavior
Made _.escape no longer translate the “>” character
Simplified all “Array” methods
Optimized _.debounce, _.escape, _.flatten, _.forEach, _.groupBy, _.intersection, _.invoke, _.isObject, _.max, _.min, _.pick, _.shuffle, _.sortedIndex, _.template, _.throttle, _.union, _.uniq

_v0.1.0

Apr. 23, 2012 — Docs

Initial release

Maintained by the core team with help from our contributors.

https://github.com/lodash/lodash.wiki.git