获取一个函数体中出现的所有变量。

getVariables.js

var KEYWORDS = "abstract,boolean,byte,char,double,final,float,goto,implements,int,interface,long,native,package,private,protected,public,short,static,synchronized,throws,transient,volatile,arguments,let,yield";
var NO_VAR_KEYWORDS={};
var REMOVE_RE = /\/\*(?:.|\n)*?\*\/|\/\/[^\n]*\n|\/\/[^\n]*$|'[^']*'|"[^"]*"|[\s\t\n]*\.[\s\t\n]*[$\w\.]+/g;
var SPLIT_RE = /[^\w$]+/g;
var KEYWORDS_RE = new RegExp(["\\b" + KEYWORDS.replace(/,/g, '\\b|\\b') + "\\b"].join('|'), 'g');
var NUMBER_RE = /\b\d[^,]*/g;
var BOUNDARY_RE = /^,+|,+$/g;
var getVariables = function(code) {
    code = code
            .replace(REMOVE_RE, '')

            .replace(SPLIT_RE, ',')


            .replace(KEYWORDS_RE, '')
            .replace(NUMBER_RE, '')
            .replace(BOUNDARY_RE, '');

    code = code ? code.split(/,+/) : [];

    for(var i = 1,Len = code.length,filterCodeArray = [],filterCodeHash = {},arg;i<Len;i+=1){//过滤关键字与重复出现的变量
        arg = code[i];
        if (!filterCodeHash[arg]&&!NO_VAR_KEYWORDS[arg]) {
            try{
                (function(k){eval("var "+k);}(arg));
            }catch(e){
                NO_VAR_KEYWORDS[arg] = 1;
                continue;
            }
            filterCodeArray.push(arg);
            filterCodeHash[arg] = 1;
        }
    }
    return filterCodeArray;
};















//*********Test**************

function test(){
    try {
        var a = 1;
        a = b;
        if (x) {
            a = c;
        };
        c = arguments;
        for(i = 0;i<Len;i+=1){
            b[i] = i;
        }
        return a+b||c;
    }catch(e){};
}

console.log(getVariables(test.toString()));