Test whether all elements in a collection fail a test implemented by a predicate function.
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var noneBy = require( '@stdlib/utils-none-by' );Tests whether all elements in a collection fail a test implemented by a predicate function.
function isPositive( value ) {
return ( value > 0 );
}
var arr = [ -1, -2, -3, -4 ];
var bool = noneBy( arr, isPositive );
// returns trueIf a predicate function returns a truthy value, the function immediately returns false.
function isPositive( value ) {
return ( value > 0 );
}
var arr = [ -1, 2, -3, -4 ];
var bool = noneBy( arr, isPositive );
// returns falseThe invoked function is provided three arguments:
value: collection elementindex: collection indexcollection: input collection
To set the function execution context, provide a thisArg.
function sum( value ) {
if ( value < 0 ) {
return true;
}
this.sum += value;
this.count += 1;
return false;
}
var arr = [ 1, 2, 3, 4 ];
var context = {
'sum': 0,
'count': 0
};
var bool = noneBy( arr, sum, context );
// returns true
var mean = context.sum / context.count;
// returns 2.5-
A
collectionmay be either anArray,Typed Array, or an array-likeObject(excludingstringsandfunctions). -
If provided an empty collection, the function returns
true.function truthy() { return true; } var bool = noneBy( [], truthy ); // returns true
-
The function does not skip
undefinedelements.function log( value, index ) { console.log( '%s: %s', index, value ); return false; } var arr = [ 1, , , 4 ]; var bool = noneBy( arr, log ); /* => 0: 1 1: undefined 2: undefined 3: 4 */
-
The function provides limited support for dynamic collections (i.e., collections whose
lengthchanges during execution).
var randu = require( '@stdlib/random-base-randu' );
var noneBy = require( '@stdlib/utils-none-by' );
function isNegative( value ) {
return ( value < 0 );
}
var bool;
var arr;
var i;
arr = new Array( 100 );
for ( i = 0; i < arr.length; i++ ) {
arr[ i ] = randu();
}
bool = noneBy( arr, isNegative );
// returns true@stdlib/utils-any-by: test whether at least one element in a collection passes a test implemented by a predicate function.@stdlib/utils-every-by: test whether all elements in a collection pass a test implemented by a predicate function.@stdlib/utils-for-each: invoke a function for each element in a collection.@stdlib/utils-none: test whether all elements in a collection are falsy.@stdlib/utils-none-by-right: test whether all elements in a collection fail a test implemented by a predicate function, iterating from right to left.@stdlib/utils-some-by: test whether a collection contains at leastnelements which pass a test implemented by a predicate function.
This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
See LICENSE.
Copyright © 2016-2023. The Stdlib Authors.
