JavaScript obfuscator

JavaScript Obfuscator is a powerful free obfuscator for JavaScript, containing a variety of features which provide protection for your source code.

Key features: - variables renaming - strings extraction and encryption - dead code injection - control flow flattening - various code transformations - and more...

The example of obfuscated code: github.com

Online version:

obfuscator.io

Plugins:

• 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

You can support this project by donating:

• (OpenCollective) https://opencollective.com/javascript-obfuscator
• PayPal credit card https://www.paypal.com/donate
• PayPal https://www.paypal.me/javascriptobfuscator
• (Bitcoin) 14yhtZxLNp6ekZAgmEmPJqEKUP2VtUxQK6

Huge thanks to all supporters!

NOTE! the README on the master branch might not match that of the latest stable release!

If you have a question, check this section first: FAQ

:warning: Important

Only obfuscate the code that belongs to you.

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.

Installation

Using Yarn or NPM

Install the package with Yarn or NPM and add it to your

dependencies

devDependencies

$ yarn add --dev javascript-obfuscator

or

sh
$ npm install --save-dev javascript-obfuscator

In a Browser

From CDN:

From

node_modules

Usage

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,
        controlFlowFlatteningThreshold: 1,
        numbersToExpressions: true,
        simplify: true,
        shuffleStringArray: true,
        splitStrings: true,
        stringArrayThreshold: 1
    }
);
console.log(obfuscationResult.getObfuscatedCode());
/*
var _0x236b = [
    '8|3|2|4|7|',
    'izyPY',
    'ZXpNn',
    'split',
    '1|5|9|6|0',
    'foo\x20',
    'xPhYQ',
    'sKneg',
    'thwwU',
    'log',
    'map'
];
(function (_0x34d326, _0xc4ba4e) {
    var _0xcd0f69 = function (_0x39b54a) {
        while (--_0x39b54a) {
            _0x34d326'push';
        }
    };
    _0xcd0f69(++_0xc4ba4e);
}(_0x236b, 0x31 + 0x42 * -0x27 + 0xbbc));
var _0x17c9 = function (_0x34d326, _0xc4ba4e) {
    _0x34d326 = _0x34d326 - (0x31 + 0x42 * -0x27 + 0x9dd);
    var _0xcd0f69 = _0x236b[_0x34d326];
    return _0xcd0f69;
};
(function () {
    var _0x32cb02 = _0x17c9, _0x41d9b4 = {
            'thwwU': _0x32cb02('0x5') + _0x32cb02('0x9'),
            'xPhYQ': function (_0x176227, _0x3e4c2d) {
                return _0x176227 + _0x3e4c2d;
            },
            'izyPY': function (_0x13389c, _0x58f8bc) {
                return _0x13389c + _0x58f8bc;
            },
            'sKneg': _0x32cb02('0xa'),
            'ZXpNn': function (_0x1e08e1, _0x5cba70) {
                return _0x1e08e1 - _0x5cba70;
            }
        }, _0x2f8df3 = _0x41d9b4[_0x32cb02('0x2')]_0x32cb02('0x8'), _0x2087f0 = -0x9a * 0x1f + 0x15 * 0x3 + 0x1267;
    while (!![]) {
        switch (_0x2f8df3[_0x2087f0++]) {
        case '0':
            console_0x32cb02('0x3');
            continue;
        case '1':
            console_0x32cb02('0x3');
            continue;
        case '2':
            var _0x39f804 = _0x41d9b4[_0x32cb02('0x0')]('5', -'2');
            continue;
        case '3':
            var _0x700005 = _0x41d9b4[_0x32cb02('0x6')]('5', 0x1818 + 0x11b5 + -0x29ca);
            continue;
        case '4':
            var _0x172286 = [
                '10',
                '10',
                '10',
                '10',
                '10'
            ]_0x32cb02('0x4');
            continue;
        case '5':
            console_0x32cb02('0x3');
            continue;
        case '6':
            console_0x32cb02('0x3');
            continue;
        case '7':
            var _0x2e20e0 = _0x41d9b4_0x32cb02('0x6')], -0x2596 + -0x27b * 0x1 + 0xdf * 0x2e), 0x1 * 0x1b06 + -0x1b8e * -0x1 + 0x1 * -0x3693);
            continue;
        case '8':
            var _0x3c882f = _0x41d9b4[_0x32cb02('0x7')]('5', 0x1dc1 * -0x1 + 0x1d59 + 0x6b);
            continue;
        case '9':
            console_0x32cb02('0x3');
            continue;
        }
        break;
    }
}());
*/

obfuscate(sourceCode, options)

Returns

ObfuscationResult

• getObfuscatedCode()

  - returns

  string

  with obfuscated code;

• getSourceMap()

  - if

  sourceMap

  option is enabled - returns

  string

  with source map or an empty string if

  sourceMapMode

  option is set as

  inline

  .

Calling

toString()

ObfuscationResult

string

Method takes two parameters,

sourceCode

options

• 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.

obfuscateMultiple(sourceCodesObject, options)

Accepts

sourceCodesObject

{
    foo: 'var foo = 1;',
    bar: 'var bar = 2;'
}

Returns a map object which keys are identifiers of source codes and values are

ObfuscationResult

getOptionsByPreset(optionsPreset)

Returns an options object for the passed options preset name.

CLI usage

See CLI options.

Obfuscate single file

Usage:

sh
javascript-obfuscator input_file_name.js [options]
javascript-obfuscator input_file_name.js --output output_file_name.js [options]
javascript-obfuscator input_file_name.js --output output_folder_name [options]
javascript-obfuscator input_folder_name --output output_folder_name [options]

Obfuscation of single input file with

.js

If the destination path is not specified with the

--output

INPUT_FILE_NAME-obfuscated.js

Some examples: ```sh 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.js ```

Obfuscate directory recursively

Usage: ``

sh
javascript-obfuscator ./dist [options]
// creates a new obfuscated files under

directory near the input files with

javascript-obfuscator ./dist --output ./dist/obfuscated [options] // creates a folder structure with obfuscated files under

./dist/obfuscated

Obfuscation of all

.js

-obfuscated

Obfuscated files will saved into the input directory under

INPUT_FILE_NAME-obfuscated.js

Conditional comments

You can disable and enable obfuscation for specific parts of the code by adding following comments: * disable:

// javascript-obfuscator:disable

/* javascript-obfuscator:disable */

// javascript-obfuscator:enable

/* javascript-obfuscator:enable */

Example: ```javascript // 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

Kind of variables of inserted nodes will auto-detected, based on most prevailing kind of variables of source code.

Conflicts of identifier names between different files

During obfuscation of the different files, the same names can be generated for the global identifiers between these files. To prevent this set the unique prefix for all global identifiers for each obfuscated file with

identifiersPrefix

When using CLI this prefix will be added automatically.

Antiviruses false positive virus alerts

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

  stringArrayEncoding

  option value between

  rc4

  and

  base64

  values or disable it completely;
• Try to change

  identifierNamesGenerator

  option value from

  hexadecimal

  on

  mangled

  ;
• Try to disable

  selfDefending

  .

If this wont help - attach your source code and describe your obfuscation options here: https://github.com/javascript-obfuscator/javascript-obfuscator/issues/51

JavaScript Obfuscator Options

Following options are available for the JS Obfuscator:

options:

{
    compact: true,
    controlFlowFlattening: false,
    controlFlowFlatteningThreshold: 0.75,
    deadCodeInjection: false,
    deadCodeInjectionThreshold: 0.4,
    debugProtection: false,
    debugProtectionInterval: false,
    disableConsoleOutput: false,
    domainLock: [],
    forceTransformStrings: [],
    identifierNamesGenerator: 'hexadecimal',
    identifiersDictionary: [],
    identifiersPrefix: '',
    inputFileName: '',
    log: false,
    numbersToExpressions: false,
    optionsPreset: 'default',
    renameGlobals: false,
    renameProperties: false,
    reservedNames: [],
    reservedStrings: [],
    rotateStringArray: true,
    seed: 0,
    selfDefending: false,
    shuffleStringArray: true,
    simplify: true,
    sourceMap: false,
    sourceMapBaseUrl: '',
    sourceMapFileName: '',
    sourceMapMode: 'separate',
    splitStrings: false,
    splitStringsChunkLength: 10,
    stringArray: true,
    stringArrayEncoding: [],
    stringArrayWrappersCount: 1,
    stringArrayWrappersChainedCalls: true,
    stringArrayWrappersType: 'variable',
    stringArrayThreshold: 0.75,
    target: 'browser',
    transformObjectKeys: false,
    unicodeEscapeSequence: false
}

CLI options:

    -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)
--force-transform-strings '<list>' (comma separated)
--identifier-names-generator <string> [dictionary, hexadecimal, mangled, mangled-shuffled]
--identifiers-dictionary '<list>' (comma separated)
--identifiers-prefix <string>
--log <boolean>
--numbers-to-expressions <boolean>
--options-preset <string> [default, low-obfuscation, medium-obfuscation, high-obfuscation]
--rename-globals <boolean>
--rename-properties <boolean>
--reserved-names '<list>' (comma separated)
--reserved-strings '<list>' (comma separated)
--rotate-string-array <boolean>
--seed <string>
--self-defending <boolean>
--shuffle-string-array <boolean>
--simplify <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 '<list>' (comma separated) [none, base64, rc4]
--string-array-wrappers-count <number>
--string-array-wrappers-chained-calls <boolean>
--string-array-wrappers-type <string> [variable, function]
--string-array-threshold <number>
--target <string> [browser, browser-no-eval, node]
--transform-object-keys <boolean>
--unicode-escape-sequence <boolean>

compact

Type:

boolean

true

Compact code output on one line.

config

Type:

string

Name of JS/JSON config file which contains obfuscator options. These will be overridden by options passed directly to CLI

controlFlowFlattening

Type:

boolean

false

:warning: 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: ```ts // 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'; continue; case '1': console'log'; continue; case '2': console'log'; continue; case '3': console'log'; continue; case '4': var _0x1f2f2f = _0x3260a5'GokKo'; continue; case '5': console'log'; continue; case '6': console'log'; continue; } break; } }; }

_0x3bfc5c()();

}()); ```

controlFlowFlatteningThreshold

Type:

number

0.75

0

1

The probability that the

controlFlowFlattening

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

controlFlowFlattening: false

deadCodeInjection

Type:

boolean

false

:warning: 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.

:warning: This option forcibly enables

stringArray

option.

With this option, random blocks of dead code will be added to the obfuscated code.

Example: ```ts // 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'); console_0x4502('0x1'); console_0x4502('0x1'); } else { console_0x4502('0x1'); console_0x4502('0x1'); console_0x4502('0x1'); console_0x4502('0x1'); } }; var _0x1f7292 = function () { if (0x4502('0x8') === 0x4502('0x9')) { console_0x4502('0x1'); console_0x4502('0x1'); console_0x4502('0x1'); } else { console_0x4502('0x1'); console_0x4502('0x1'); console_0x4502('0x1'); } }; var _0x33b212 = function () { if (0x4502('0xd') !== _0x4502('0xe')) { console_0x4502('0x1'); console_0x4502('0x1'); console_0x4502('0x1'); } else { console_0x4502('0x1'); console_0x4502('0x1'); console_0x4502('0x1'); console_0x4502('0x1'); } }; _0x16c18d(); _0x1f7292(); _0x33b212(); } }()); ```

deadCodeInjectionThreshold

Type:

number

0.4

0

1

Allows to set percentage of nodes that will affected by

deadCodeInjection

debugProtection

Type:

boolean

false

:warning: Can freeze your browser if you open the Developer Tools.

This option makes it almost impossible to use the

debugger

debugProtectionInterval

Type:

boolean

false

:warning: Can freeze your browser! Use at own risk.

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

disableConsoleOutput

Type:

boolean

false

Disables the use of

console.log

console.info

console.error

console.warn

console.debug

console.exception

console.trace

domainLock

Type:

string[]

[]

:warning: This option does not work with

target: 'node'

Allows to run the obfuscated source code only on specific domains and/or sub-domains. This makes really hard for someone to just copy and paste your source code and run it elsewhere.

Multiple domains and sub-domains

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

example.com

sub.example.com

.example.com

exclude

Type:

string[]

[]

A file names or globs which indicates files to exclude from obfuscation.

forceTransformStrings

Type:

string[]

[]

Enables force transformation of string literals, which being matched by passed RegExp patterns.

:warning: This option affects only strings that shouldn't be transformed by

stringArrayThreshold

(or possible other thresholds in the future)

The option has a priority over

reservedStrings

conditional comments

Example:

ts
    {
        forceTransformStrings: [
            'some-important-value',
            'some-string_\d'
        ]
    }

identifierNamesGenerator

Type:

string

hexadecimal

Sets identifier names generator.

Available values: *

dictionary

identifiersDictionary

hexadecimal

_0xabc123

mangled

a

b

c

mangled-shuffled

mangled

identifiersDictionary

Type:

string[]

[]

Sets identifiers dictionary for

identifierNamesGenerator

dictionary

identifiersPrefix

Type:

string

''

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.

inputFileName

Type:

string

''

Allows to set name of the input file with source code. This name will be used internally for source map generation.

log

Type:

boolean

false

Enables logging of the information to the console.

numbersToExpressions

Type:

boolean

false

Enables numbers conversion to expressions

Example: ```ts // input const foo = 1234;

// output const foo=-0xd93+-0x10b4+0x410x67+0x84e0x3+-0xff8; ```

optionsPreset

Type:

string

default

Allows to set options preset.

Available values: *

default

low-obfuscation

medium-obfuscation

high-obfuscation

All addition options will be merged with selected options preset.

renameGlobals

Type:

boolean

false

:warning: this option can break your code. Enable it only if you know what it does!

Enables obfuscation of global variable and function names with declaration.

renameProperties

Type:

boolean

false

:warning: this option WILL break your code in most cases. Enable it only if you know what it does!

Enables renaming of property names. All built-in DOM properties and properties in core JavaScript classes will be ignored.

To set format of renamed property names use

identifierNamesGenerator

To control which properties will be renamed use

reservedNames

Example: ```ts // input (function () { const foo = { prop1: 1, prop2: 2, calc: function () { return this.prop1 + this.prop2; } };

console.log(foo.calc());

})();

// output (function () { const 0x46529b = { '0x10cec7': 0x1, '0xc1c0ca': 0x2, '0x4b961d': function () { return this['0x10cec7'] + this['0xc1c0ca']; } }; console'log'; }()); ```

reservedNames

Type:

string[]

[]

Disables obfuscation and generation of identifiers, which being matched by passed RegExp patterns.

Example:

ts
    {
        reservedNames: [
            '^someVariable',
            'functionParameter_\d'
        ]
    }

reservedStrings

Type:

string[]

[]

Disables transformation of string literals, which being matched by passed RegExp patterns.

Example:

ts
    {
        reservedStrings: [
            'react-native',
            '\.\/src\/test',
            'some-string_\d'
        ]
    }

rotateStringArray

Type:

boolean

true

:warning:

stringArray

must be enabled

Shift the

stringArray

This option is recommended if your original source code isn't small, as the helper function can attract attention.

seed

Type:

string|number

0

This option sets seed for random generator. This is useful for creating repeatable results.

If seed is

0

selfDefending

Type:

boolean

false

:warning: 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!

:warning: This option forcibly sets

compact

value to

true

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.

shuffleStringArray

Type:

boolean

true

:warning:

stringArray

must be enabled

Randomly shuffles the

stringArray

simplify

Type:

boolean

true

Enables additional code obfuscation through simplification.

:warning: in future releases obfuscation of

boolean

literals (

true

=>

!![]

) will be moved under this option.

Example: ```ts // input if (condition1) { const foo = 1; const bar = 2;

console.log(foo);

return bar;

} else if (condition2) { console.log(1); console.log(2); console.log(3);

return 4;

} else { return 5; }

// output if (condition1) { const foo = 0x1, bar = 0x2; return console'log', bar; } else return condition2 ? (console'log', console'log', console'log', 0x4) : 0x5; ```

sourceMap

Type:

boolean

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.

sourceMapBaseUrl

Type:

string

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

sourceMapFileName

Type:

string

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

sourceMapMode

Type:

string

separate

Specifies source map generation mode: *

inline

separate

//# sourceMappingUrl=file.js.map

splitStrings

Type:

boolean

false

Splits literal strings into chunks with length of

splitStringsChunkLength

Example: ```ts // input (function(){ var test = 'abcdefg'; })();

// output (function(){ var _0x5a21 = 'ab' + 'cd' + 'ef' + 'g'; })(); ```

splitStringsChunkLength

Type:

number

10

Sets chunk length of

splitStrings

stringArray

Type:

boolean

true

Removes string literals and place them in a special array. For instance, the string

"Hello World"

var m = "Hello World";

var m = _0x12c456[0x1];

stringArrayEncoding

Type:

string[]

[]

:warning:

stringArray

option must be enabled

This option can slow down your script.

Encode all string literals of the

stringArray

base64

rc4

Each

stringArray

Available values: *

'none'

boolean

stringArray

'base64'

string

stringArray

base64

'rc4'

string

stringArray

rc4

base64

unicodeEscapeSequence

rc4

For example with the following option values some

stringArray

base64

rc4

stringArrayEncoding: [
    'none',
    'base64',
    'rc4'
]

stringArrayWrappersCount

Type:

number

1

:warning:

stringArray

option must be enabled

Sets the count of wrappers for the

string array

literal

Example: ```ts // Input const foo = 'foo'; const bar = 'bar';

function test () { const baz = 'baz'; const bark = 'bark'; const hawk = 'hawk'; }

const eagle = 'eagle';

// Output, stringArrayWrappersCount: 5 const 0x3018 = [ 'foo', 'bar', 'baz', 'bark', 'hawk', 'eagle' ]; const _0x380f = function (0x30182a, 0x380f29) { _0x30182a = _0x30182a - 0x0; let _0x4e002c = _0x3018[0x30182a]; return _0x4e002c; }; const _0xe4db7c = _0x380f; const _0x26ca42 = _0x380f; const _0x58c610 = _0x380f; const foo = _0x58c610('0x0'); const bar = _0x26ca42('0x1'); function test() { const _0x500eda = _0x380f; const _0x1d1760 = _0x380f; const _0x4ca8b0 = _0x380f; const _0x4e002c = _0x4ca8b0('0x2'); const _0x573b1c = _0x1d1760('0x3'); const _0x1fb6ef = _0x500eda('0x4'); } const eagle = _0x26ca42('0x5'); ```

stringArrayWrappersChainedCalls

Type:

boolean

true

:warning:

stringArray

and

stringArrayWrappersCount

options must be enabled

Enables the chained calls between

string array

Example: ```ts // Input const foo = 'foo'; const bar = 'bar';

function test () { const baz = 'baz'; const bark = 'bark';

function test1() {
    const hawk = 'hawk';
    const eagle = 'eagle';
} 

}

// Output, stringArrayWrappersCount: 5, stringArrayWrappersChainedCalls: true const 0x4714 = [ 'foo', 'bar', 'baz', 'bark', 'hawk', 'eagle' ]; const _0x2bdb = function (0x471439, 0x2bdb71) { _0x471439 = _0x471439 - 0x0; let _0x6e47e6 = _0x4714[0x471439]; return _0x6e47e6; }; const _0x1c3d52 = _0x2bdb; const _0xd81c2a = _0x2bdb; const foo = _0xd81c2a('0x0'); const bar = _0x1c3d52('0x1'); function test() { const _0x21a0b4 = _0x1c3d52; const _0x12842d = _0xd81c2a; const _0x6e47e6 = _0x12842d('0x2'); const _0x4f3aef = _0x12842d('0x3'); function _0x40f1dc() { const _0x468540 = _0x12842d; const _0x1f4b05 = _0x21a0b4; const _0x40a980 = _0x1f4b05('0x4'); const _0x4d1285 = _0x468540('0x5'); } } ```

stringArrayWrappersType

Type:

string

variable

:warning:

stringArray

and

stringArrayWrappersCount

options must be enabled

Allows to select a type of the wrappers that are appending by the

stringArrayWrappersCount

Available values: *

'variable'

'function'

variable

stringArray

Highly recommended to use

function

Example of the

'function'

function test () { const bar = 'bar'; }

// output const a = [ 'foo', 'bar' ]; const b = function (c, d) { c = c - 0x0; let e = a[c]; return e; }; const d = function (c, f) { return b(c - '0x372', f); }; const foo = d('0x372'); function test() { const e = function (c, f) { return d(c - -'0x260', f); }; const c = e('0x113'); } ```

stringArrayThreshold

Type:

number

0.8

0

1

:warning:

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

stringArrayThreshold: 0

stringArray: false

target

Type:

string

browser

Allows to set target environment for obfuscated code.

Available values: *

browser

browser-no-eval

node

Currently output code for

browser

node

node

browser-no-eval

eval

transformObjectKeys

Type:

boolean

false

Enables transformation of object keys.

Example: ```ts // input (function(){ var object = { foo: 'test1', bar: { baz: 'test2' } }; })();

// output var 0x2fae = [ 'baz', 'test2', 'foo', 'test1', 'bar' ]; var _0x377c = function (0x1fbd3f, 0x59c72f) { _0x1fbd3f = _0x1fbd3f - 0x0; var _0x14fada = _0x2fae[0x1fbd3f]; return 0x14fada; }; (function () { var _0x8a12db = {}; _0x8a12db[0x377c('0x0')] = 0x377c('0x1'); var _0xc75419 = {}; _0xc75419[0x377c('0x2')] = 0x377c('0x3'); _0xc75419[0x377c('0x4')] = _0x8a12db; var _0x191393 = _0xc75419; }()); ```

unicodeEscapeSequence

Type:

boolean

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.

Preset Options

High obfuscation, low performance

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,
    numbersToExpressions: true,
    renameGlobals: false,
    rotateStringArray: true,
    selfDefending: true,
    shuffleStringArray: true,
    simplify: true,
    splitStrings: true,
    splitStringsChunkLength: 5,
    stringArray: true,
    stringArrayEncoding: ['rc4'],
    stringArrayWrappersCount: 5,
    stringArrayWrappersChainedCalls: true,
    stringArrayWrappersType: 'function',
    stringArrayThreshold: 1,
    transformObjectKeys: true,
    unicodeEscapeSequence: false
}

Medium obfuscation, optimal performance

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,
    numbersToExpressions: true,
    renameGlobals: false,
    rotateStringArray: true,
    selfDefending: true,
    shuffleStringArray: true,
    simplify: true,
    splitStrings: true,
    splitStringsChunkLength: 10,
    stringArray: true,
    stringArrayEncoding: ['base64'],
    stringArrayWrappersCount: 2,
    stringArrayWrappersChainedCalls: true,
    stringArrayWrappersType: 'variable',
    stringArrayThreshold: 0.75,
    transformObjectKeys: true,
    unicodeEscapeSequence: false
}

Low obfuscation, High performance

Performance will slightly slower than without obfuscation

{
    compact: true,
    controlFlowFlattening: false,
    deadCodeInjection: false,
    debugProtection: false,
    debugProtectionInterval: false,
    disableConsoleOutput: true,
    identifierNamesGenerator: 'hexadecimal',
    log: false,
    numbersToExpressions: false,
    renameGlobals: false,
    rotateStringArray: true,
    selfDefending: true,
    shuffleStringArray: true,
    simplify: true,
    splitStrings: false,
    stringArray: true,
    stringArrayEncoding: [],
    stringArrayWrappersCount: 1,
    stringArrayWrappersChainedCalls: true,
    stringArrayWrappersType: 'variable',
    stringArrayThreshold: 0.75,
    unicodeEscapeSequence: false
}

Default preset, High performance

{
    compact: true,
    controlFlowFlattening: false,
    deadCodeInjection: false,
    debugProtection: false,
    debugProtectionInterval: false,
    disableConsoleOutput: false,
    identifierNamesGenerator: 'hexadecimal',
    log: false,
    numbersToExpressions: false,
    renameGlobals: false,
    rotateStringArray: true,
    selfDefending: false,
    shuffleStringArray: true,
    simplify: true,
    splitStrings: false,
    stringArray: true,
    stringArrayEncoding: [],
    stringArrayWrappersCount: 1,
    stringArrayWrappersChainedCalls: true,
    stringArrayWrappersType: 'variable',
    stringArrayThreshold: 0.75,
    unicodeEscapeSequence: false
}

Frequently Asked Questions

What javascript versions are supported?

es3

es5

es2015

es2016

es2017

es2018

es2019

es2020

I want to use feature that described in

README.md

but it's not working!

The README on the master branch might not match that of the latest stable release.

Why CLI command not working?

Try to run

npm link javascript-obfuscator

npm i -g javascript-obfuscator

Error

maximum call stack size exceeded

Likely this is

selfDefending

selfDefending

Online version?

obfuscator.io

JSX support?

No. JSX support isn't planned.

How to change kind of variables of inserted nodes (

var

,

let

or

const

)?

See:

Kind of variables

Why I got

null

value instead of

BigInt

number?

BigInt

BigInt

I enabled

renameProperties

option, and my code broke! What to do?

Just disable this option.

Backers

Support us with a monthly donation and help us continue our activities. [Become a backer]

Sponsors

Become a sponsor and get your logo on our README on Github with a link to your site. [Become a sponsor]

License

Copyright (C) 2016-2020 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.