JavaScript Obfuscator is a powerful free obfuscator for JavaScript, containing a variety of features which provide protection for your source code.
Example of obfuscated code: gist.github.com
- Webpack plugin: webpack-obfuscator
- Webpack loader: obfuscator-loader
- Gulp: gulp-javascript-obfuscator
- Grunt: grunt-contrib-obfuscator
- Rollup: rollup-plugin-javascript-obfuscator
- Weex: weex-devtool
- Malta: malta-js-obfuscator
- (Bitcoin) 14yhtZxLNp6ekZAgmEmPJqEKUP2VtUxQK6
- (Ether) 0x5Df9eBcFB2D0f3315d03Ac112104b9023C409dc1
- (OpenCollective) https://opencollective.com/javascript-obfuscator
Huge thanks to all supporters!
If you have a question, check this section first: FAQ
It is not recommended to obfuscate vendor scripts and polyfills, since the obfuscated code is 15-80% slower (depends on options) and the files are significantly larger.
Install the package with Yarn or NPM and add it to your dependencies or devDependencies:
$ yarn add --dev javascript-obfuscatoror
$ npm install --save-dev javascript-obfuscatorFrom CDN:
<script src="https://cdn.jsdelivr.net/npm/javascript-obfuscator/dist/index.browser.js"></script>From node_modules:
<script src="./node_modules/javascript-obfuscator/dist/index.browser.js"></script>var JavaScriptObfuscator = require('javascript-obfuscator');
var obfuscationResult = JavaScriptObfuscator.obfuscate(
`
(function(){
var variable1 = '5' - 3;
var variable2 = '5' + 3;
var variable3 = '5' + - '2';
var variable4 = ['10','10','10','10','10'].map(parseInt);
var variable5 = 'foo ' + 1 + 1;
console.log(variable1);
console.log(variable2);
console.log(variable3);
console.log(variable4);
console.log(variable5);
})();
`,
{
compact: false,
controlFlowFlattening: true
}
);
console.log(obfuscationResult.getObfuscatedCode());
/*
var _0x2218 = [
'8|3|1|2|0|4|6|9|7|5',
'bqndd',
'dySIh',
'kTiiG',
'log',
'tuvgv'
];
(function (_0x38b423, _0x1d6bd4) {
var _0x39a849 = function (_0x5794c7) {
while (--_0x5794c7) {
_0x38b423['push'](_0x38b423['shift']());
}
};
_0x39a849(++_0x1d6bd4);
}(_0x2218, 0x114));
var _0x8221 = function (_0xcac13e, _0x3627d7) {
_0xcac13e = _0xcac13e - 0x0;
var _0x1eae4d = _0x2218[_0xcac13e];
return _0x1eae4d;
};
(function () {
var _0x5336d5 = {
'bqndd': _0x8221('0x0'),
'islRd': function _0x2abb6c(_0x2f45f8, _0x4d47b0) {
return _0x2f45f8 + _0x4d47b0;
},
'kTiiG': function _0x32525a(_0x44ba8d, _0x2c5e0c) {
return _0x44ba8d + _0x2c5e0c;
},
'dySIh': 'foo\x20',
'tuvgv': function _0x28d015(_0x35d81a, _0x2d2463) {
return _0x35d81a - _0x2d2463;
}
};
var _0x5000ba = _0x5336d5[_0x8221('0x1')]['split']('|'), _0x5c972f = 0x0;
while (!![]) {
switch (_0x5000ba[_0x5c972f++]) {
case '0':
var _0x586faa = _0x5336d5['islRd'](_0x5336d5['kTiiG'](_0x5336d5[_0x8221('0x2')], 0x1), 0x1);
continue;
case '1':
var _0xab6a82 = _0x5336d5[_0x8221('0x3')]('5', -'2');
continue;
case '2':
var _0x19ab9d = [
'10',
10000
'10',
'10',
'10',
'10'
]['map'](parseInt);
continue;
case '3':
var _0x321653 = _0x5336d5[_0x8221('0x3')]('5', 0x3);
continue;
case '4':
console['log'](_0x2c1b0c);
continue;
case '5':
console[_0x8221('0x4')](_0x586faa);
continue;
case '6':
console[_0x8221('0x4')](_0x321653);
continue;
case '7':
console[_0x8221('0x4')](_0x19ab9d);
continue;
case '8':
var _0x2c1b0c = _0x5336d5[_0x8221('0x5')]('5', 0x3);
continue;
case '9':
console[_0x8221('0x4')](_0xab6a82);
continue;
}
break;
}
}());
*/Returns ObfuscationResult object which contains two public methods:
getObfuscatedCode()- returnsstringwith obfuscated code;getSourceMap()- ifsourceMapoption is enabled - returnsstringwith source map or an empty string ifsourceMapModeoption is set asinline.
Calling toString() for ObfuscationResult object will return string with obfuscated code.
Method takes two parameters, sourceCode and options – the source code and the opitons respectively:
sourceCode(string, default:null) – any valid source code, passed as a string;options(Object, default:null) – an object with options.
For available options, see options.
See CLI options.
Usage:
javascript-obfuscator input_file_name.js [options]
javascript-obfuscator input_file_name.js --output output_file_name.js [options]Obfuscation of single input file with .js extension.
If the destination path is not specified with the --output option, the obfuscated file will be saved into the input file directory, with INPUT_FILE_NAME-obfuscated.js name.
Some examples:
javascript-obfuscator samples/sample.js --compact true --self-defending false
// creates a new file samples/sample-obfuscated.js
javascript-obfuscator samples/sample.js --output output/output.js --compact true --self-defending false
// creates a new file output/output.jsUsage:
javascript-obfuscator ./dist [options]
// creates a new obfuscated files under `./dist` directory near the input files with `obfuscated` postfix
javascript-obfuscator ./dist --output ./dist/obfuscated [options]
// creates a folder structure with obfuscated files under `./dist/obfuscated` pathObfuscation of all .js files under input directory. If this directory contains already obfuscated files with -obfuscated postfix - these files will ignored.
Obfuscated files will saved into the input directory under INPUT_FILE_NAME-obfuscated.js name.
You can disable and enable obfuscation for specific parts of the code by adding following comments:
- disable:
// javascript-obfuscator:disableor/* javascript-obfuscator:disable */; - enable:
// javascript-obfuscator:enableor/* javascript-obfuscator:enable */.
Example:
// input
var foo = 1;
// javascript-obfuscator:disable
var bar = 2;
// output
var _0xabc123 = 0x1;
var bar = 2;Conditional comments affect only direct transformations of AST-tree nodes. All child transformations still will be applied to the AST-tree nodes.
For example:
- Obfuscation of the variable's name at its declaration is called direct transformation;
- Obfuscation of the variable's name beyond its declaration is called child transformation.
Kind of variables of inserted nodes will auto-detected, based on most prevailing kind of variables of source code.
Some input source code that will obfuscated with some obfuscation options can trigger false positive alerts in a few antiviruses. If you will get this false positive triggers, try to play with obfuscation options.
- Try to change
stringArrayEncodingoption value betweenrc4andbase64values or disable it completely; - Try to change
identifierNamesGeneratoroption value fromhexadecimalonmangled; - Try to disable
selfDefending.
If this wont help - attach your source code and describe your obfuscation options here: javascript-obfuscator#51
Following options are available for the JS Obfuscator:
{
compact: true,
controlFlowFlattening: false,
controlFlowFlatteningThreshold: 0.75,
deadCodeInjection: false,
deadCodeInjectionThreshold: 0.4,
debugProtection: false,
debugProtectionInterval: false,
disableConsoleOutput: false,
domainLock: [],
identifierNamesGenerator: 'hexadecimal',
identifiersDictionary: [],
identifiersPrefix: '',
inputFileName: '',
log: false,
renameGlobals: false,
reservedNames: [],
reservedStrings: [],
rotateStringArray: true,
seed: 0,
selfDefending: false,
sourceMap: false,
sourceMapBaseUrl: '',
sourceMapFileName: '',
sourceMapMode: 'separate',
splitStrings: false,
splitStringsChunkLength: 10,
stringArray: true,
stringArrayEncoding: false,
stringArrayThreshold: 0.75,
target: 'browser',
transformObjectKeys: false,
unicodeEscapeSequence: false
} -v, --version
-h, --help
-o, --output
--compact <boolean>
--config <string>
--control-flow-flattening <boolean>
--control-flow-flattening-threshold <number>
--dead-code-injection <boolean>
--dead-code-injection-threshold <number>
--debug-protection <boolean>
--debug-protection-interval <boolean>
--disable-console-output <boolean>
--domain-lock '<list>' (comma separated)
--exclude '<list>' (comma separated)
--identifier-names-generator <string> [dictionary, hexadecimal, mangled]
--identifiers-dictionary '<list>' (comma separated)
--identifiers-prefix <string>
--log <boolean>
--rename-globals <boolean>
--reserved-names '<list>' (comma separated)
--reserved-strings '<list>' (comma separated)
--rotate-string-array <boolean>
--seed <string|number>
--self-defending <boolean>
--source-map <boolean>
--source-map-base-url <string>
--source-map-file-name <string>
--source-map-mode <string> [inline, separate]
--split-strings <boolean>
--split-strings-chunk-length <number>
--string-array <boolean>
--string-array-encoding <boolean|string> [true, false, base64, rc4]
--string-array-threshold <number>
--target <string> [browser, browser-no-eval, node]
--transform-object-keys <boolean>
--unicode-escape-sequence <boolean>Type: boolean Default: true
Compact code output on one line.
Type: string Default: ``
Name of JS/JSON config file which contains obfuscator options. These will be overridden by options passed directly to CLI
Type: boolean Default: false
⚠️ This option greatly affects the performance up to 1.5x slower runtime speed. Use controlFlowFlatteningThreshold to set percentage of nodes that will affected by control flow flattening.
Enables code control flow flattening. Control flow flattening is a structure transformation of the source code that hinders program comprehension.
Example:
// input
(function(){
function foo () {
return function () {
var sum = 1 + 2;
console.log(1);
console.log(2);
console.log(3);
console.log(4);
console.log(5);
console.log(6);
}
}
foo()();
})();
// output
(function () {
function _0x3bfc5c() {
return function () {
var _0x3260a5 = {
'WtABe': '4|0|6|5|3|2|1',
'GokKo': function _0xf87260(_0x427a8e, _0x43354c) {
return _0x427a8e + _0x43354c;
}
};
var _0x1ad4d6 = _0x3260a5['WtABe']['split']('|'), _0x1a7b12 = 0x0;
while (!![]) {
switch (_0x1ad4d6[_0x1a7b12++]) {
case '0':
console['log'](0x1);
continue;
case '1':
console['log'](0x6);
continue;
case '2':
console['log'](0x5);
continue;
case '3':
console['log'](0x4);
continue;
case '4':
var _0x1f2f2f = _0x3260a5['GokKo'](0x1, 0x2);
continue;
case '5':
console['log'](0x3);
continue;
case '6':
console['log'](0x2);
continue;
}
break;
}
};
}
_0x3bfc5c()();
}());Type: number Default: 0.75 Min: 0 Max: 1
The probability that the controlFlowFlattening transformation will be applied to the node.
This setting is especially useful for large code size because large amounts of control flow transformations can slow down your code and increase code size.
controlFlowFlatteningThreshold: 0 equals to controlFlowFlattening: false.
Type: boolean Default: false
⚠️ Dramatically increases size of obfuscated code (up to 200%), use only if size of obfuscated code doesn't matter. Use deadCodeInjectionThreshold to set percentage of nodes that will affected by dead code injection.
With this option random blocks of dead code will add to the obfuscated code.
Example:
// input
(function(){
if (true) {
var foo = function () {
console.log('abc');
console.log('cde');
console.log('efg');
console.log('hij');
};
var bar = function () {
console.log('klm');
console.log('nop');
console.log('qrs');
};
var baz = function () {
console.log('tuv');
console.log('wxy');
console.log('z');
};
foo();
bar();
baz();
}
})();
// output
var _0x5024 = [
'zaU',
'log',
'tuv',
'wxy',
'abc',
'cde',
'efg',
'hij',
'QhG',
'TeI',
'klm',
'nop',
'qrs',
'bZd',
'HMx'
];
var _0x4502 = function (_0x1254b1, _0x583689) {
_0x1254b1 = _0x1254b1 - 0x0;
var _0x529b49 = _0x5024[_0x1254b1];
return _0x529b49;
};
(function () {
if (!![]) {
var _0x16c18d = function () {
if (_0x4502('0x0') !== _0x4502('0x0')) {
console[_0x4502('0x1')](_0x4502('0x2'));
console[_0x4502('0x1')](_0x4502('0x3'));
console[_0x4502('0x1')]('z');
} else {
console[_0x4502('0x1')](_0x4502('0x4'));
console[_0x4502('0x1')](_0x4502('0x5'));
console[_0x4502('0x1')](_0x4502('0x6'));
console[_0x4502('0x1')](_0x4502('0x7'));
}
};
var _0x1f7292 = function () {
if (_0x4502('0x8') === _0x4502('0x9')) {
console[_0x4502('0x1')](_0x4502('0xa'));
console[_0x4502('0x1')](_0x4502('0xb'));
console[_0x4502('0x1')](_0x4502('0xc'));
} else {
console[_0x4502('0x1')](_0x4502('0xa'));
console[_0x4502('0x1')](_0x4502('0xb'));
console[_0x4502('0x1')](_0x4502('0xc'));
}
F987
};
var _0x33b212 = function () {
if (_0x4502('0xd') !== _0x4502('0xe')) {
console[_0x4502('0x1')](_0x4502('0x2'));
console[_0x4502('0x1')](_0x4502('0x3'));
console[_0x4502('0x1')]('z');
} else {
console[_0x4502('0x1')](_0x4502('0x4'));
console[_0x4502('0x1')](_0x4502('0x5'));
console[_0x4502('0x1')](_0x4502('0x6'));
console[_0x4502('0x1')](_0x4502('0x7'));
}
};
_0x16c18d();
_0x1f7292();
_0x33b212();
}
}());Type: number Default: 0.4 Min: 0 Max: 1
Allows to set percentage of nodes that will affected by deadCodeInjection.
Type: boolean Default: false
This option makes it almost impossible to use the console tab of the Developer Tools (both on WebKit-based and Mozilla Firefox).
- WebKit-based: blocks the site window, but you still can navigate through Developer Tools panel.
- Firefox: does not block the site window, but still won't let you use DevTools.
Type: boolean Default: false
If checked, an interval is used to force the debug mode on the Console tab, making it harder to use other features of the Developer Tools. Works if debugProtection is enabled.
Type: boolean Default: false
Disables the use of console.log, console.info, console.error, console.warn, console.debug, console.exception and console.trace by replacing them with empty functions. This makes the use of the debugger harder.
Type: string[] Default: []
Locks the obfuscated source code so it only runs on specific domains and/or sub-domains. This makes really hard for someone just copy and paste your source code and run elsewhere.
It's possible to lock your code to more than one domain or sub-domain. For instance, to lock it so the code only runs on www.example.com add www.example.com, to make it work on any sub-domain from example.com, use .example.com.
Type: string[] Default: []
A file names or globs which indicates files to exclude from obfuscation.
Type: string Default: hexadecimal
Sets identifier names generator.
Available values:
dictionary: identifier names fromidentifiersDictionarylisthexadecimal: identifier names like_0xabc123mangled: short identifier names likea,b,c
Type: string[] Default: []
Sets identifiers dictionary for identifierNamesGenerator: dictionary option
Type: string Default: ''
Sets prefix for all global identifiers.
Use this option when you want to obfuscate multiple files. This option helps to avoid conflicts between global identifiers of these files. Prefix should be different for every file.
Type: string Default: ''
Allows to set name of the input file with source code. This name will used internally for source map generation.
Type: boolean Default: false
Enables logging of the information to the console.
Type: boolean Default: false
Enables obfuscation of global variable and function names with declaration.
Type: string[] Default: []
Disables obfuscation and generation of identifiers, which being matched by passed RegExp patterns.
Example:
{
reservedNames: [
'^someVariable',
'functionParameter_\d'
]
}Type: string[] Default: []
Disables transformation of string literals, which being matched by passed RegExp patterns.
Example:
{
reservedStrings: [
'react-native',
'\.\/src\/test',
'some-string_\d'
]
}Type: boolean Default: true
⚠️ stringArray must be enabled
Shift the stringArray array by a fixed and random (generated at the code obfuscation) places. This makes it harder to match the order of the removed strings to their original place.
This option is recommended if your original source code isn't small, as the helper function can attract attention.
Type: string|number Default: 0
This option sets seed for random generator. This is useful for creating repeatable results.
If seed is 0 - random generator will work without seed.
Type: boolean Default: false
⚠️ Don't change obfuscated code in any way after obfuscation with this option, because any change like uglifying of code can trigger self defending and code wont work anymore!
This option makes the output code resilient against formatting and variable renaming. If one tries to use a JavaScript beautifier on the obfuscated code, the code won't work anymore, making it harder to understand and modify it.
Type: boolean Default: false
Enables source map generation for obfuscated code.
Source maps can be useful to help you debug your obfuscated JavaScript source code. If you want or need to debug in production, you can upload the separate source map file to a secret location and then point your browser there.
Type: string Default: ``
Sets base url to the source map import url when sourceMapMode: 'separate'.
CLI example:
javascript-obfuscator input.js --output out.js --source-map true --source-map-base-url 'http://localhost:9000'
Result:
//# sourceMappingURL=http://localhost:9000/out.js.map
Type: string Default: ``
Sets file name for output source map when sourceMapMode: 'separate'.
CLI example:
javascript-obfuscator input.js --output out.js --source-map true --source-map-base-url 'http://localhost:9000' --source-map-file-name example
Result:
//# sourceMappingURL=http://localhost:9000/example.js.map
Type: string Default: separate
Specifies source map generation mode:
inline- emit a single file with source maps instead of having a separate file;separate- generates corresponding '.map' file with source map. In case you run obfuscator through CLI - adds link to source map file to the end of file with obfuscated code//# sourceMappingUrl=file.js.map.
Type: boolean Default: false
Splits literal strings into chunks with length of splitStringsChunkLength option value.
Example:
// input
(function(){
var test = 'abcdefg';
})();
// output
(function(){
var _0x5a21 = 'ab' + 'cd' + 'ef' + 'g';
})();Type: number Default: 10
Sets chunk length of splitStrings option.
Type: boolean Default: true
Removes string literals and place them in a special array. For instance, the string "Hello World" in var m = "Hello World"; will be replaced with something like var m = _0x12c456[0x1];
Type: boolean|string Default: false
This option can slow down your script.
Encode all string literals of the stringArray using base64 or rc4 and inserts a special code that used to decode it back at runtime.
Available values:
true(boolean): encodestringArrayvalues usingbase64false(boolean): don't encodestringArrayvalues'base64'(string): encodestringArrayvalues usingbase64'rc4'(string): encodestringArrayvalues usingrc4. About 30-50% slower thanbase64, but more harder to get initial values. It is recommended to disableunicodeEscapeSequenceoption withrc4encoding to prevent very large size of obfuscated code.
Type: number Default: 0.8 Min: 0 Max: 1
⚠️ stringArray option must be enabled
You can use this setting to adjust the probability (from 0 to 1) that a string literal will be inserted into the stringArray.
This setting is especially useful for large code size because it repeatedly calls to the string array and can slow down your code.
stringArrayThreshold: 0 equals to stringArray: false.
Type: string Default: browser
Allows to set target environment for obfuscated code.
Available values:
browser;browser-no-eval;node.
Currently output code for browser and node targets is identical.
Output code for browser-no-eval target is not using eval.
Type: boolean Default: false
Enables transformation of object keys.
Example:
// input
(function(){
var object = {
foo: 'test1',
bar: {
baz: 'test2'
}
};
})();
// output
var _0x5a21 = [
'foo',
'test1',
'bar',
'baz',
'test2'
];
var _0x223f = function (_0x474dc0, _0x10db96) {
_0x474dc0 = _0x474dc0 - 0x0;
var _0x4c8bf7 = _0x5a21[_0x474dc0];
return _0x4c8bf7;
};
(function () {
var _0x2e1a8e = {};
_0x2e1a8e[_0x223f('0x0')] = _0x223f('0x1');
_0x2e1a8e[_0x223f('0x2')] = {};
_0x2e1a8e[_0x223f('0x2')][_0x223f('0x3')] = _0x223f('0x4');
}());Type: boolean Default: false
Allows to enable/disable string conversion to unicode escape sequence.
Unicode escape sequence increases code size greatly and strings easily can be reverted to their original view. Recommended to enable this option only for small source code.
Performance will 50-100% slower than without obfuscation
{
compact: true,
controlFlowFlattening: true,
controlFlowFlatteningThreshold: 1,
deadCodeInjection: true,
deadCodeInjectionThreshold: 1,
debugProtection: true,
debugProtectionInterval: true,
disableConsoleOutput: true,
identifierNamesGenerator: 'hexadecimal',
log: false,
renameGlobals: false
1241
,
rotateStringArray: true,
selfDefending: true,
splitStrings: true,
splitStringsChunkLength: '5',
stringArray: true,
stringArrayEncoding: 'rc4',
stringArrayThreshold: 1,
transformObjectKeys: true,
unicodeEscapeSequence: false
}Performance will 30-35% slower than without obfuscation
{
compact: true,
controlFlowFlattening: true,
controlFlowFlatteningThreshold: 0.75,
deadCodeInjection: true,
deadCodeInjectionThreshold: 0.4,
debugProtection: false,
debugProtectionInterval: false,
disableConsoleOutput: true,
identifierNamesGenerator: 'hexadecimal',
log: false,
renameGlobals: false,
rotateStringArray: true,
selfDefending: true,
splitStrings: true,
splitStringsChunkLength: '10',
stringArray: true,
stringArrayEncoding: 'base64',
stringArrayThreshold: 0.75,
transformObjectKeys: true,
unicodeEscapeSequence: false
}Performance will slightly slower than without obfuscation
{
compact: true,
controlFlowFlattening: false,
deadCodeInjection: false,
debugProtection: false,
debugProtectionInterval: false,
disableConsoleOutput: true,
identifierNamesGenerator: 'hexadecimal',
log: false,
renameGlobals: false,
rotateStringArray: true,
selfDefending: true,
splitStrings: false,
stringArray: true,
stringArrayEncoding: false,
stringArrayThreshold: 0.75,
unicodeEscapeSequence: false
}es3, es5, es2015, es2016 and es2017
The README on the master branch might not match that of the latest stable release.
Try to run npm link javascript-obfuscator command or install it globally with npm i -g javascript-obfuscator
Likely this is selfDefending mechanism. Something is changing source code after obfuscation with selfDefending option.
No. JSX support isn't planned.
See: Kind of variables
Support us with a monthly donation and help us continue our activities. [Become a backer]
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Copyright (C) 2016-2018 Timofey Kachalov.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.