Escope (escope) is ECMAScript scope analyzer extracted from esmangle project.

Example

var escope = require('escope');
var esprima = require('esprima');
var estraverse = require('estraverse');

var ast = esprima.parse(code);
var scopeManager = escope.analyze(ast);

var currentScope = scopeManager.acquire(ast);   // global scope

estraverse.traverse(ast, {
    enter: function(node, parent) {
        // do stuff
        
        if (/Function/.test(node.type)) {
            currentScope = scopeManager.acquire(node);  // get current function scope
        }
    },
    leave: function(node, parent) {
        if (/Function/.test(node.type)) {
            currentScope = currentScope.upper;  // set to parent scope
        }
        
        // do stuff
    }
});

Document

Generated JSDoc is here.

Demos and Tools

Demonstration is here by Sasha Mazurov (twitter: @mazurov). issue

And there are tools constructed on Escope.

• Esmangle is a minifier / mangler / optimizer.
• Eslevels is a scope levels analyzer and SublimeText plugin for scope context coloring is constructed on it.
• Esgoggles is JavaScript code browser.

License

Copyright (C) 2012-2013 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.