splice(start: number, deleteCount: number, ...elements: T[]): T[] {
		const before = this.getRenderedItemRanges();
		const inserted = elements.map<IItem<T>>(element => ({
			id: String(this.itemId++),
			element,
			size: this.delegate.getHeight(element),
			templateId: this.delegate.getTemplateId(element),
			row: null
		}));

		this.rangeMap.splice(start, deleteCount, ...inserted);
		const deleted = this.items.splice(start, deleteCount, ...inserted);

		const after = this.getRenderedItemRanges();
		const lcs = new LcsDiff(toSequence(before), toSequence(after), null);
		const diffs = lcs.ComputeDiff();

		for (const diff of diffs) {
			for (let i = 0; i < diff.originalLength; i++) {
				this.removeItemFromDOM(before[diff.originalStart + i].item);
			}

			for (let i = 0; i < diff.modifiedLength; i++) {
				this.insertItemInDOM(after[diff.modifiedStart + i].item, after[0].index + diff.modifiedStart + i);
			}
		}

		const scrollHeight = this.getContentHeight();
		this.rowsContainer.style.height = `${ scrollHeight }px`;
		this.scrollableElement.updateState({ scrollHeight });

		return deleted.map(i => i.element);
	}

	test('using continue processing predicate to quit early', function () {
		var left = 'abcdef';
		var right = 'abxxcyyydzzzzezzzzzzzzzzzzzzzzzzzzf';

		// We use a long non-matching portion at the end of the right-side string, so the backwards tracking logic
		// doesn't get there first.
		var predicateCallCount = 0;

		var diff = new LcsDiff(new StringDiffSequence(left), new StringDiffSequence(right), function (leftIndex, leftSequence, longestMatchSoFar) {
			assert.equal(predicateCallCount, 0);

			predicateCallCount++;

			assert.equal(leftSequence.getLength(), left.length);
			assert.equal(leftIndex, 1);

			// cancel processing
			return false;
		});
		var changes = diff.ComputeDiff(true);

		assert.equal(predicateCallCount, 1);

		// Doesn't include 'c', 'd', or 'e', since we quit on the first request
		assertAnswer(left, right, changes, 'abf');



		// Cancel after the first match ('c')
		diff = new LcsDiff(new StringDiffSequence(left), new StringDiffSequence(right), function (leftIndex, leftSequence, longestMatchSoFar) {
			assert(longestMatchSoFar <= 1); // We never see a match of length > 1

			// Continue processing as long as there hasn't been a match made.
			return longestMatchSoFar < 1;
		});
		changes = diff.ComputeDiff(true);

		assertAnswer(left, right, changes, 'abcf');



		// Cancel after the second match ('d')
		diff = new LcsDiff(new StringDiffSequence(left), new StringDiffSequence(right), function (leftIndex, leftSequence, longestMatchSoFar) {
			assert(longestMatchSoFar <= 2); // We never see a match of length > 2

			// Continue processing as long as there hasn't been a match made.
			return longestMatchSoFar < 2;
		});
		changes = diff.ComputeDiff(true);

		assertAnswer(left, right, changes, 'abcdf');



		// Cancel *one iteration* after the second match ('d')
		var hitSecondMatch = false;
		diff = new LcsDiff(new StringDiffSequence(left), new StringDiffSequence(right), function (leftIndex, leftSequence, longestMatchSoFar) {
			assert(longestMatchSoFar <= 2); // We never see a match of length > 2

			var hitYet = hitSecondMatch;
			hitSecondMatch = longestMatchSoFar > 1;
			// Continue processing as long as there hasn't been a match made.
			return !hitYet;
		});
		changes = diff.ComputeDiff(true);

		assertAnswer(left, right, changes, 'abcdf');



		// Cancel after the third and final match ('e')
		diff = new LcsDiff(new StringDiffSequence(left), new StringDiffSequence(right), function (leftIndex, leftSequence, longestMatchSoFar) {
			assert(longestMatchSoFar <= 3); // We never see a match of length > 3

			// Continue processing as long as there hasn't been a match made.
			return longestMatchSoFar < 3;
		});
		changes = diff.ComputeDiff(true);

		assertAnswer(left, right, changes, 'abcdef');
	});

function computeDiff(originalSequence: ISequence, modifiedSequence: ISequence, continueProcessingPredicate: () => boolean, pretty: boolean): IDiffChange[] {
	const diffAlgo = new LcsDiff(originalSequence, modifiedSequence, continueProcessingPredicate);
	return diffAlgo.ComputeDiff(pretty);
}