WIP towards #984

Author: Rich-Harris

src/compile/nodes/Binding.ts

@@ -14,6 +14,9 @@ const readOnlyMediaAttributes = new Set([
 	'played'
 ]);
 
+// TODO a lot of this element-specific stuff should live in Element —
+// Binding should ideally be agnostic between Element and Component
+
 export default class Binding extends Node {
 	name: string;
 	value: Expression;
@@ -57,7 +60,10 @@ export default class Binding extends Node {
 		const node: Element = this.parent;
 
 		const needsLock = node.name !== 'input' || !/radio|checkbox|range|color/.test(node.getStaticAttributeValue('type'));
-		const isReadOnly = node.isMediaNode() && readOnlyMediaAttributes.has(this.name);
+		const isReadOnly = (
+			(node.isMediaNode() && readOnlyMediaAttributes.has(this.name)) ||
+			this.name === 'width' || this.name === 'height'
+		);
 
 		let updateCondition: string;
 
@@ -103,8 +109,7 @@ export default class Binding extends Node {
 		if (this.name === 'currentTime' || this.name === 'volume') {
 			updateCondition = `!isNaN(${snippet})`;
 
-			if (this.name === 'currentTime')
-				initialUpdate = null;
+			if (this.name === 'currentTime') initialUpdate = null;
 		}
 
 		if (this.name === 'paused') {
@@ -117,6 +122,12 @@ export default class Binding extends Node {
 			initialUpdate = null;
 		}
 
+		// bind:width and bind:height
+		if (this.name === 'width' || this.name === 'height') {
+			initialUpdate = null;
+			updateDom = null;
+		}
+
 		return {
 			name: this.name,
 			object: name,

src/compile/nodes/Element.ts

@@ -262,7 +262,7 @@ export default class Element extends Node {
 			parentNode;
 
 		block.addVariable(name);
-		const renderStatement = getRenderStatement(this.compiler, this.namespace, this.name);
+		const renderStatement = getRenderStatement(this.namespace, this.name);
 		block.builders.create.addLine(
 			`${name} = ${renderStatement};`
 		);
@@ -916,7 +916,6 @@ export default class Element extends Node {
 }
 
 function getRenderStatement(
-	compiler: Compiler,
 	namespace: string,
 	name: string
 ) {
@@ -971,6 +970,12 @@ const events = [
 			node.name === 'input' && /radio|checkbox|range/.test(node.getStaticAttributeValue('type'))
 	},
 
+	{
+		eventNames: ['resize'],
+		filter: (node: Element, name: string) =>
+			(name === 'width' || name === 'height')
+	},
+
 	// media events
 	{
 		eventNames: ['timeupdate'],

src/shared/dom.js

@@ -193,3 +193,28 @@ export function selectMultipleValue(select) {
 		return option.__value;
 	});
 }
+
+export function addResizeListener(element, fn) {
+	if (getComputedStyle(element).position === 'static') {
+		element.style.position = 'relative';
+	}
+
+	const object = document.createElement('object');
+	object.setAttribute('style', 'display: block; position: absolute; top: 0; left: 0; height: 100%; width: 100%; overflow: hidden; pointer-events: none; z-index: -1;');
+	object.type = 'text/html';
+
+	if (isIE) element.appendChild(object);
+	object.data = 'about:blank';
+	if (!isIE) element.appendChild(object);
+
+	object.onload = () => {
+		object.contentDocument.defaultView.addEventListener('resize', fn);
+	};
+
+	return {
+		cancel: () => {
+			object.contentDocument.defaultView.removeEventListener('resize', fn);
+			element.removeChild(object);
+		}
+	};
+}

src/validate/html/validateElement.ts

@@ -157,7 +157,7 @@ export default function validateElement(
 						message: `'${name}' binding can only be used with <audio> or <video>`
 					});
 				}
-			} else {
+			} else if (name !== 'width' && name !== 'height') {
 				validator.error(attribute, {
 					code: `invalid-binding`,
 					message: `'${attribute.name}' is not a valid binding`

test/js/samples/bind-width-height.solo/expected-bundle.js

@@ -0,0 +1,178 @@
+function noop() {}
+
+function assign(tar, src) {
+	for (var k in src) tar[k] = src[k];
+	return tar;
+}
+
+function insertNode(node, target, anchor) {
+	target.insertBefore(node, anchor);
+}
+
+function detachNode(node) {
+	node.parentNode.removeChild(node);
+}
+
+function createElement(name) {
+	return document.createElement(name);
+}
+
+function blankObject() {
+	return Object.create(null);
+}
+
+function destroy(detach) {
+	this.destroy = noop;
+	this.fire('destroy');
+	this.set = noop;
+
+	if (detach !== false) this._fragment.u();
+	this._fragment.d();
+	this._fragment = null;
+	this._state = {};
+}
+
+function _differs(a, b) {
+	return a != a ? b == b : a !== b || ((a && typeof a === 'object') || typeof a === 'function');
+}
+
+function fire(eventName, data) {
+	var handlers =
+		eventName in this._handlers && this._handlers[eventName].slice();
+	if (!handlers) return;
+
+	for (var i = 0; i < handlers.length; i += 1) {
+		var handler = handlers[i];
+
+		if (!handler.__calling) {
+			handler.__calling = true;
+			handler.call(this, data);
+			handler.__calling = false;
+		}
+	}
+}
+
+function get() {
+	return this._state;
+}
+
+function init(component, options) {
+	component._handlers = blankObject();
+	component._bind = options._bind;
+
+	component.options = options;
+	component.root = options.root || component;
+	component.store = component.root.store || options.store;
+}
+
+function on(eventName, handler) {
+	var handlers = this._handlers[eventName] || (this._handlers[eventName] = []);
+	handlers.push(handler);
+
+	return {
+		cancel: function() {
+			var index = handlers.indexOf(handler);
+			if (~index) handlers.splice(index, 1);
+		}
+	};
+}
+
+function set(newState) {
+	this._set(assign({}, newState));
+	if (this.root._lock) return;
+	this.root._lock = true;
+	callAll(this.root._beforecreate);
+	callAll(this.root._oncreate);
+	callAll(this.root._aftercreate);
+	this.root._lock = false;
+}
+
+function _set(newState) {
+	var oldState = this._state,
+		changed = {},
+		dirty = false;
+
+	for (var key in newState) {
+		if (this._differs(newState[key], oldState[key])) changed[key] = dirty = true;
+	}
+	if (!dirty) return;
+
+	this._state = assign(assign({}, oldState), newState);
+	this._recompute(changed, this._state);
+	if (this._bind) this._bind(changed, this._state);
+
+	if (this._fragment) {
+		this.fire("state", { changed: changed, current: this._state, previous: oldState });
+		this._fragment.p(changed, this._state);
+		this.fire("update", { changed: changed, current: this._state, previous: oldState });
+	}
+}
+
+function callAll(fns) {
+	while (fns && fns.length) fns.shift()();
+}
+
+function _mount(target, anchor) {
+	this._fragment[this._fragment.i ? 'i' : 'm'](target, anchor || null);
+}
+
+function _unmount() {
+	if (this._fragment) this._fragment.u();
+}
+
+var proto = {
+	destroy,
+	get,
+	fire,
+	on,
+	set,
+	_recompute: noop,
+	_set,
+	_mount,
+	_unmount,
+	_differs
+};
+
+/* generated by Svelte vX.Y.Z */
+
+function create_main_fragment(component, ctx) {
+	var div;
+
+	return {
+		c: function create() {
+			div = createElement("div");
+			div.textContent = "some content";
+		},
+
+		m: function mount(target, anchor) {
+			insertNode(div, target, anchor);
+
+			div.width = ctx.width ;
+			div.height = ctx.height;
+		},
+
+		p: noop,
+
+		u: function unmount() {
+			detachNode(div);
+		},
+
+		d: noop
+	};
+}
+
+function SvelteComponent(options) {
+	init(this, options);
+	this._state = assign({}, options.data);
+
+	this._fragment = create_main_fragment(this, this._state);
+
+	if (options.target) {
+		this._fragment.c();
+		this._mount(options.target, options.anchor);
+	}
+}
+
+assign(SvelteComponent.prototype, proto);
+
+export default SvelteComponent;

test/js/samples/bind-width-height.solo/expected.js

@@ -0,0 +1,50 @@
+/* generated by Svelte vX.Y.Z */
+import { addResizeListener, assign, createElement, detachNode, init, insertNode, noop, proto } from "svelte/shared.js";
+
+function create_main_fragment(component, ctx) {
+	var div, div_resize_listener;
+
+	function div_resize_handler() {
+		component.set({ w: div.offsetWidth, h: offsetHeight });
+	}
+
+	return {
+		c: function create() {
+			div = createElement("div");
+			div.textContent = "some content";
+		},
+
+		h: function hydrate() {
+			div_resize_listener = addResizeListener(div, div_resize_handler);
+			component._beforecreate.push(div_resize_handler);
+		},
+
+		m: function mount(target, anchor) {
+			insertNode(div, target, anchor);
+		},
+
+		p: noop,
+
+		u: function unmount() {
+			div_resize_listener.cancel();
+			detachNode(div);
+		},
+
+		d: noop
+	};
+}
+
+function SvelteComponent(options) {
+	init(this, options);
+	this._state = assign({}, options.data);
+
+	this._fragment = create_main_fragment(this, this._state);
+
+	if (options.target) {
+		this._fragment.c();
+		this._mount(options.target, options.anchor);
+	}
+}
+
+assign(SvelteComponent.prototype, proto);
+export default SvelteComponent;

test/js/samples/bind-width-height.solo/input.html

@@ -0,0 +1,3 @@
+<div bind:width=w bind:height=h>
+	some content
+</div>