eachSeries should finish if underlying array is modified

What version of async are you using? 2.2.0

Which environment did the issue occur in (Node version/browser version) nodejs 7.7.3

What did you do? Please include a minimal reproducable case illustrating issue.

	it("async.eachSeries : add an element in underlying array while iterating should finish iteration, per docs", function(testDone) {

		var data = [1, 2, 3, 4, 5];
		var results = [];
		var iterator = function(collection, item, eachDone) {

			console.log("we process item =" + item);

			results.push(item);
			if (item === 2) {
				// we add "new" after 2
				collection.splice(2, 0, "new");
			}
			return eachDone();

		};

		async.eachSeries(data, iterator.bind(null, data), function(err) {

			expect(err).to.be.not.exist;

			// we expect the iteration to finish after have processed value 2, but actually, the iteration continues, but with respect to the original array length
			expect(results).to.have.length(2);

			testDone();
		});

	});

What did you expect to happen?

According to changelog v1.10 : eachSeries and family will finish if the underlying array is modified during execution (#557) I did not find more recent reference to this topic.

So I expected the iteration to stop after have modified the array

What was the actual result?

The iterations continue, but only according to the original length of the array

FWIW, I need to add elements (and so iterations) to the array while iterating, that’s why I was testing this behaviour.

[abenhamdine]

Ah yes queue seems a good candidate for my use case, thx 👍 . Though shouldn’t the docs be updated to warn about the immutability of the collection ? I dont’ find any reference to this, eg in http://caolan.github.io/async/docs.html#each, except the changelog of old v1.10 I mentioned.

If you are open to a PR for the docs, where in the docs do you think it would be the most relevant ?

[aearly]

@nakiabrewer doWhilst or queue might be better suited to your task. (Iterate while body.data.next_page exists, or keep pushing new pages to the queue.)