proxyHelpers.js

function assertOrderOfOps(act, exp) {
    exp.forEach(function(e, i) {
        if(act[i][0] !== exp[i][0] || act[i][1] !== exp[i][1]) {
            throw new Error('Expected operation ' + i + ' to be ' + exp[i] + ' but was ' + act[i]);
        }
    });

    if(act.length > exp.length) {
        throw new Error('More operations than expected: ' +
            act.slice(exp.length).map(function(e) { return e[0] })
        );
    }
}

function createLoggerProxy(obj) {
    var ops = [];
    var proxy = new Proxy(obj, new Proxy({}, {
        get: function(o, v, r) {
            return function() {
                ops.push([v, arguments[1]]);

                return Reflect[v].apply(this, arguments);
            }
        }
    }))

    return {
        log: ops,
        proxy: proxy
    }
}

Example test case (can run in firefox with tvcutsem's Reflect polyfill script included):

var arr = [0];
var res = createLoggerProxy(arr);
var p = res.proxy;
var log = res.log;
p.pop();
assertOrderOfOps(res.log, [
    ['get', 'pop'],
    ['get', 'length'],
    ['get', '0'],
    ['delete', '0'],
    ['set', 'length']
]);

Small snippet to include the polyfill in your current context:

var s = document.createElement('script'); s.src = 'https://rawgithub.com/tvcutsem/harmony-reflect/master/reflect.js'; document.body.appendChild(s);

Brian,
Based upon spec bug reports I've received, I think the Chrome guys may already be using something like this