Repository: chartjs/Chart.js
File: src/platforms/platform.dom.js (JavaScript)

Code before:

	node.classList.add(CSS_RENDER_MONITOR);
}

function unwatchForRender(node) {
	var expando = node[EXPANDO_KEY] || {};
	var proxy = expando.renderProxy;

	if (proxy) {
		helpers.each(ANIMATION_START_EVENTS, function(type) {
			removeEventListener(node, type, proxy);
		});

		delete expando.renderProxy;
	}

	node.classList.remove(CSS_RENDER_MONITOR);
}

function addResizeListener(node, listener, chart) {
	var expando = node[EXPANDO_KEY] = node[EXPANDO_KEY] || {};

	// Let's keep track of this added resizer and thus avoid DOM query when removing it.
	var resizer = expando.resizer = createResizer(throttled(function() {
		if (expando.resizer) {
			var aspectRatio = chart.options.maintainAspectRatio && chart.aspectRatio || null;
			var container = aspectRatio && node.parentNode;
			var w = container ? container.clientWidth : 0;
			var ret = listener(createEvent('resize', chart));
			if (container && container.clientWidth !== w && chart.canvas) {
				// If the container size changed during chart resize, we can assume scrollbar appeared.
				// So let's resize again, with the scrollbar visible
				ret = listener(createEvent('resize', chart));
			}
			return ret;
		}
	}));

	// The resizer needs to be attached to the node parent, so we first need to be
	// sure that `node` is attached to the DOM before injecting the resizer element.
	watchForRender(node, function() {
		if (expando.resizer) {
			var container = node.parentNode;
			if (container && container !== resizer.parentNode) {
				container.insertBefore(resizer, container.firstChild);
			}

			// The container size might have changed, let's reset the resizer state.
			resizer._reset();
		}
	});

Review comment (suggestion):
`var aspectRatio = chart.options.maintainAspectRatio;` should be enough

Code after:

	node.classList.add(CSS_RENDER_MONITOR);
}

function unwatchForRender(node) {
	var expando = node[EXPANDO_KEY] || {};
	var proxy = expando.renderProxy;

	if (proxy) {
		helpers.each(ANIMATION_START_EVENTS, function(type) {
			removeEventListener(node, type, proxy);
		});

		delete expando.renderProxy;
	}

	node.classList.remove(CSS_RENDER_MONITOR);
}

function addResizeListener(node, listener, chart) {
	var expando = node[EXPANDO_KEY] || (node[EXPANDO_KEY] = {});

	// Let's keep track of this added resizer and thus avoid DOM query when removing it.
	var resizer = expando.resizer = createResizer(throttled(function() {
		if (expando.resizer) {
			var container = chart.options.maintainAspectRatio && node.parentNode;
			var w = container ? container.clientWidth : 0;
			listener(createEvent('resize', chart));
			if (container && container.clientWidth < w && chart.canvas) {
				// If the container size shrank during chart resize, let's assume
				// scrollbar appeared. So we resize again with the scrollbar visible -
				// effectively making chart smaller and the scrollbar hidden again.
				// Because we are inside `throttled`, and currently `ticking`, scroll
				// events are ignored during this whole 2 resize process.
				// If we assumed wrong and something else happened, we are resizing
				// twice in a frame (potential performance issue)
				listener(createEvent('resize', chart));
			}
		}
	}));

	// The resizer needs to be attached to the node parent, so we first need to be
	// sure that `node` is attached to the DOM before injecting the resizer element.
	watchForRender(node, function() {
		if (expando.resizer) {
			var container = node.parentNode;
			if (container && container !== resizer.parentNode) {
				container.insertBefore(resizer, container.firstChild);
			}

			// The container size might have changed, let's reset the resizer state.