Esmangle

esmangle (esmangle) is mangler / minifier for Mozilla Parser API AST.

Install

esmangle can be used in a web browser:

<script src="esmangle.js"></script>

or in a Node.js application via the package manager:

npm install esmangle

Usage

A simple example: the program

var ast = esprima.parse(code);
var result = esmangle.mangle(ast);  // gets mangled result
console.log(escodegen.generate(result));  // dump AST

Or you can simply use this esmangle command in the shell.

esmangle file.js

Get more compressed result: (in Node.js)

var ast = esprima.parse(code);
// You can add your original pass
// See lib/pass/*.js for pass function format
var passes = [
    // transform dynamic to static property access
    esmangle.require('lib/pass/transform-dynamic-to-static-property-access'),

    // reordering function declaration
    esmangle.require('lib/pass/reordering-function-declarations'),

    // remove unused label
    esmangle.require('lib/pass/remove-unused-label'),

    // remove empty statement
    esmangle.require('lib/pass/remove-empty-statement'),

    // remove wasted blocks
    esmangle.require('lib/pass/remove-wasted-blocks'),

    // transform to sequence expression
    esmangle.require('lib/pass/transform-to-sequence-expression'),

    // transform branch to expression
    esmangle.require('lib/pass/transform-branch-to-expression'),

    // reduce sequence expression
    esmangle.require('lib/pass/reduce-sequence-expression'),

    // reduce branch jump
    esmangle.require('lib/pass/reduce-branch-jump'),

    // dead code elimination
    esmangle.require('lib/pass/dead-code-elimination')
];

// And you can add original post processes
var post = [
    esmangle.require('lib/post/transform-static-to-dynamic-property-access'),
    esmangle.require('lib/post/rewrite-boolean'),
    esmangle.require('lib/post/rewrite-conditional-expression')
];

// Get optimized AST
var optimized = esmangle.optimize(ast, passes);
optimized = post.reduce(function (tree, p) {
    return p(tree);
}, optimized);

// gets mangled AST
var result = esmangle.mangle(optimized);
console.log(escodegen.generate(result, {
    format: {
        renumber: true,
        hexadecimal: true,
        escapeless: true,
        compact: true,
        semicolons: false,
        parentheses: false
    }
}));  // dump AST

Demo

Code

Result

Note

This resolution algorithm is based on my bytecode compiler iv / lv5 / railgun.

License

Copyright (C) 2012 Yusuke Suzuki (twitter: @Constellation) and other contributors.

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.