Theseus

Tom Lieber · alltom.com

Joel Brandt · joelbrandt.org

Debugging async code is fun!

#amirite #yolo

Something's wrong!

Guess at the problem

Add breakpoints, logs

Reload

Fixed yet?

github.com/adobe-research/theseus

Instabug

Peter Flynn · github.com/peterflynn

Live JS Editing

Function replacement

function myFunc() {
    console.log('old message');
}

function myFunc() {
    var func, funcDef = __funcReplacements['myFunc'];
    if (funcDef) {
        func = eval(funcDef);
    } else {
        func = function () {    
            console.log('old message');
        }
    }
    return func.apply(this, arguments);
}

__funcReplacements['myFunc'] = 
    '(function () { console.log(\'new message\'); })';

Adding items to existing closures

var myModule = (function () {
    var someVar = 1;
    var myFunc = function () { console.log(someVar); };
    return { myFunc: myFunc };
}());

...user makes edits...

var myModule = (function () {
    var someVar = 1;
    var myFunc = function () { console.log(newFunc()); };
    var newFunc = function () { return someVar; };
    return { myFunc: myFunc };
}());

The grotesque hack: "with"

var someObj = {
    name: "Some Guy",
    age: 21
};

with (someObj) {
    console.log("Name: " + name + ", age: " + age);
}

Applying the grotesqueness

var myModule = (function () {
    __scopes['myModule'] = {};
    with (__scopes['myModule']) {
        var someVar = 1;
        var myFunc = function () { /* instrumented version */ };
    }
    scope.someVar = someVar;
    scope.myFunc = myFunc;
    return { myFunc: myFunc };
}());

with (__scopes['myModule']) {
    var newFunc = function () { return someVar; };
}
__scopes['myModule'].newFunc = newFunc;

Why, God, Why?

Response

Lee Brimelow · leebrimelow.com