freeze-proxy.js - mozsearch

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/* Any copyright is dedicated to the Public Domain.

 * http://creativecommons.org/publicdomain/zero/1.0/ */

function logProxy(object = {}, handler = {}) {

    var log = [];

    var proxy = new Proxy(object, new Proxy(handler, {

        get(target, propertyKey, receiver) {

            log.push(propertyKey);

            return target[propertyKey];

    }));

    return {proxy, log};

// The order of operations is backwards when compared to ES6 draft rev 27

// (2014 August 24), but see https://bugs.ecmascript.org/show_bug.cgi?id=3215

// for an explanation on why the spec version is clearly wrong.

var {proxy, log} = logProxy();

Object.freeze(proxy);

assertDeepEq(log, ["preventExtensions", "ownKeys"]);

var {proxy, log} = logProxy();

Object.freeze(Object.freeze(proxy));

assertDeepEq(log, ["preventExtensions", "ownKeys", "preventExtensions", "ownKeys"]);

reportCompare(0, 0);