sequence.js

CancellablePromise.sequence = function(values) {
    var children = [];

    return new A.CancellablePromise(
        function(resolve, reject) {
            if (!A.Lang.isArray(values)) {
                reject(new TypeError('CancellablePromise.sequence expects an array of values or promises'));
                return;
            }

            var instance = this,
                child,
                results = [],
                remaining = values.length;

            function resolveInternal(childPos, val) {
                results[childPos-1] = val;
                remaining--;
                if (!remaining) {
                    resolve(results);
                }
            }

            A.Array.each(values, function(maybePromise) {
                child = A.CancellablePromise.resolve(maybePromise);
                child = child.then(
                    A.rbind(resolveInternal, instance, children.push(child)),
                    A.bind(instance.cancel, instance));
            });
        },
        function() {
            A.Array.invoke(children, 'cancel');
            children = null;
        }
    );
};

usage.js

Y.CancellablePromise.sequence([
      delay(100, 1),
      delay(500, 2),
      new Y.CancellablePromise(function (res, rej) { setTimeout(function() { rej(2.1); }, 600); }),
      delay(1000, 3),
      delay(2000, 4)
  ])
  .then(function(data) {
      console.log(data);
  },
  function(reason) {
      console.log('rejected', reason);
  });