Miller

miller.js

var fs = require("fs");
var jsp = require("uglify-js").parser;
var pro = require("uglify-js").uglify;

fs.readFile(process.argv[2], "utf8", function(err, data) {
    if (err) throw err;
    var ast = jsp.parse(data);
    var w = pro.ast_walker(), walk = w.walk;
    var vars = {};

    var _vardef = function(exp, args) {
        for (ndx in exp) {
            vars[exp[ndx][0]] = true;
        }
    };

    w.with_walkers({
        'name': function(exp, args) {
            var literals = {
                'true' : true,
                'false' : true,
                'null' : true,
                'this' : true
            };
            if (!literals[exp]) {
                vars[exp] = true;
            }
        },
        'var': _vardef,
        'const': _vardef
    }, function() { return walk(pro.ast_add_scope(ast)); });
    for (v in vars) {
        console.log(v);
    }
});