Progression migration

Progression has been removed as there are composability and chaining issues with APIs that use promise progression handlers. Implementing the common use case of progress bars can be accomplished using a pattern similar to IProgress in C#.

For old code that still uses it, see the progression docs in the deprecated API documentation.

Using jQuery before:

Promise.resolve($.get(...))
    .progressed(function() {
        // ...
    })
    .then(function() {
        // ...
    })
    .catch(function(e) {
        // ...
    })

Using jQuery after:

Promise.resolve($.get(...).progress(function() {
        // ...
    }))
    .then(function() {
        // ...
    })
    .catch(function(e) {
        // ...
    })

Implementing general progress interfaces like in C#:

function returnsPromiseWithProgress(progressHandler) {
    return doFirstAction().tap(function() {
        progressHandler(0.33);
    }).then(doSecondAction).tap(function() {
        progressHandler(0.66);
    }).then(doThirdAction).tap(function() {
        progressHandler(1.00);
    });
}

returnsPromiseWithProgress(function(progress) {
    ui.progressbar.setWidth((progress * 200) + "px"); // update width on client side
}).then(function(value) { // action complete
   // entire chain is complete.
}).catch(function(e) {
    // error
});

Another example using coroutine:

var doNothing = function() {};
var progressSupportingCoroutine = Promise.coroutine(function* (progress) {
        progress = typeof progress === "function" ? progress : doNothing;
        var first = yield getFirstValue();
        // 33% done
        progress(0.33);
        var second = yield getSecondValue();
        progress(0.67);
        var third = yield getThirdValue();
        progress(1);
        return [first, second, third];
});

var progressConsumingCoroutine = Promise.coroutine(function* () {
    var allValues = yield progressSupportingCoroutine(function(p) {
         ui.progressbar.setWidth((p * 200) + "px");
    });
    var second = allValues[1];
    // ...
});