JavaScript obfuscator is a powerful free obfuscator for JavaScript and Node.js with a wide number of features which provides protection for your source code.
- has no limits or restrictions
- runs on your local machine - does not send data to a server;
- compatible with
es2015,es2016and partiallyes2017; - tested on Angular2 bundle.
Online version: javascriptobfuscator.herokuapp.com
Example of obfuscated code: gist.github.com
- Webpack: webpack-obfuscator
- Gulp: gulp-javascript-obfuscator
- Grunt: grunt-contrib-obfuscator
- Rollup: rollup-plugin-javascript-obfuscator
NOTE! the README on the master branch might not match that of the latest stable release!
If this project helps you, you can support it:
- (Bitcoin) 1EnQsZc35CjVy92HN9gZXHjjMnqiW6BsGF
- (OpenCollective) https://opencollective.com/javascript-obfuscator
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 devDependencies:
$ yarn add --dev javascript-obfuscatoror
$ npm install --save-dev javascript-obfuscatorHere's an example of how to use it:
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',
'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, obfuscated file will saved into the input file directory with INPUT_FILE_NAME-obfuscated.js name.
Examples:
javascript-obfuscator samples/sample.js --compact true --selfDefending false
// creates a new file samples/sample-obfuscated.js
javascript-obfuscator samples/sample.js --output output/output.js --compact true --selfDefending false
// creates a new file output/output.jsUsage:
javascript-obfuscator input_directory_name [options]Obfuscation 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.
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: [],
log: false,
mangle: false,
renameGlobals: false,
reservedNames: [],
rotateStringArray: true,
seed: 0,
selfDefending: false,
sourceMap: false,
sourceMapBaseUrl: '',
sourceMapFileName: '',
sourceMapMode: 'separate',
stringArray: true,
stringArrayEncoding: false,
stringArrayThreshold: 0.75,
target: 'browser',
unicodeEscapeSequence: false
} -v, --version
-h, --help
-o, --output
--compact <boolean>
--config <string>
--controlFlowFlattening <boolean>
--controlFlowFlatteningThreshold <number>
--deadCodeInjection <boolean>
--deadCodeInjectionThreshold <number>
--debugProtection <boolean>
--debugProtectionInterval <boolean>
--disableConsoleOutput <boolean>
--domainLock '<list>' (comma separated)
--log <boolean>
--mangle <boolean>
--renameGlobals <boolean>
--reservedNames '<list>' (comma separated)
--rotateStringArray <boolean>
--seed <number>
--selfDefending <boolean>
--sourceMap <boolean>
--sourceMapBaseUrl <string>
--sourceMapFileName <string>
--sourceMapMode <string> [inline, separate]
--stringArray <boolean>
--stringArrayEncoding <boolean|string> [true, false, base64, rc4]
--stringArrayThreshold <number>
--target <string> [browser, extension, node]
--unicodeEscapeSequence <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'));
}
};
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: boolean Default: false
Enables logging of the information to the console.
Type: boolean Default: false
Enables mangling of variable names.
Type: boolean Default: false
Enables obfuscation of global variable and function names with declaration.
Type: string[] Default: []
Disables the obfuscation of variables names, function names and function parameters that match the Regular Expression used.
Example:
{
reservedNames: [
'^someVariable',
'functionParameter_\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: 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 --sourceMap true --sourceMapBaseUrl '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 --sourceMap true --sourceMapBaseUrl 'http://localhost:9000' --sourceMapFileName 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: 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 slightly 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;extension;node.
Currently output code for browser and node targets is identical.
Output code for extension target is not using eval.
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,
log: false,
mangle: false,
renameGlobals: false,
rotateStringArray: true,
selfDefending: true,
stringArray: true,
stringArrayEncoding: 'rc4',
stringArrayThreshold: 1,
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,
log: false,
mangle: false,
renameGlobals: false,
rotateStringArray: true,
selfDefending: true,
stringArray: true,
stringArrayEncoding: 'base64',
stringArrayThreshold: 0.75,
unicodeEscapeSequence: false
}Performance will slightly slower than without obfuscation
{
compact: true,
controlFlowFlattening: false,
deadCodeInjection: false,
debugProtection: false,
debugProtectionInterval: false,
disableConsoleOutput: true,
log: false,
mangle: true,
renameGlobals: false,
rotateStringArray: true,
selfDefending: true,
stringArray: true,
stringArrayEncoding: false,
stringArrayThreshold: 0.75,
unicodeEscapeSequence: false
}Support us with a monthly donation and help us continue our activities. [Become a backer]
Become a sponsor and get your logo on our README on Github with a link to your site. [Become a sponsor]
Copyright (C) 2017 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.