leak.js

(function (global, known) {
    global.dev = global.dev || {};

    function register(str) {
        known[str] = str;
    }

    function raiseError(leaks) {
        if (leaks && leaks.length) {
            throw new Error("global leak" +
                (leaks.length > 1 ? "s" : "") +
                " detected: " + leaks.join(", "));
        }
    }

    function fromKnown(key) {
        return key !== known[key];
    }
    
    global.dev.checkGlobals = function (debug) {
        var obj = {}, type, val, leaks = Object.keys(global).filter(fromKnown);
        if (debug) {
            leaks.forEach(function (leak) {
                val = global[leak];
                type = typeof val;
                obj[type] = obj[type] || {};
                obj[type][leak] = val;
            });
            console.log("global leak detected:");
            console.dir(obj);
        } else {
            raiseError(leaks);
        }
    };
    global.dev.registerAllGlobals = function () {
        Object.keys(global).forEach(register);
    };
    global.dev.registerGlobal = register;
}(this, {}));

if (Object.keys && Array.prototype.forEach) {
    dev.registerAllGlobals();
}