How to use Promise.all with an object as input

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First of all: Scrap that Promise constructor, this usage is an antipattern!

Now, to your actual problem: As you have correctly identified, you are missing the key for each value. You will need to pass it inside each promise, so that you can reconstruct the object after having awaited all items:

function mapObjectToArray(obj, cb) {
    var res = [];
    for (var key in obj)
        res.push(cb(obj[key], key));
    return res;
}

return Promise.all(mapObjectToArray(input, function(arg, key) {
    return getPromiseFor(arg, key).then(function(value) {
         return {key: key, value: value};
    });
}).then(function(arr) {
    var obj = {};
    for (var i=0; i<arr.length; i++)
        obj[arr[i].key] = arr[i].value;
    return obj;
});

Mightier libraries such as Bluebird will also provide this as a helper function, like Promise.props.

Also, you shouldn’t use that pseudo-recursive load function. You can simply chain promises together:

….then(function (resources) {
    return game.scripts.reduce(function(queue, script) {
        return queue.then(function() {
            return getScript(root + script);
        });
    }, Promise.resolve()).then(function() {
        return resources;
    });
});

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