svelte/shared.js

The magical disappearing UI framework

function noop() {}

function assign(target) {
	var k,
		source,
		i = 1,
		len = arguments.length;
	for (; i < len; i++) {
		source = arguments[i];
		for (k in source) target[k] = source[k];
	}

	return target;
}

function appendNode(node, target) {
	target.appendChild(node);
}

function insertNode(node, target, anchor) {
	target.insertBefore(node, anchor);
}

function detachNode(node) {
	node.parentNode.removeChild(node);
}

function detachBetween(before, after) {
	while (before.nextSibling && before.nextSibling !== after) {
		before.parentNode.removeChild(before.nextSibling);
	}
}

// TODO this is out of date
function destroyEach(iterations, detach, start) {
	for (var i = start; i < iterations.length; i += 1) {
		if (iterations[i]) iterations[i].destroy(detach);
	}
}

function createElement(name) {
	return document.createElement(name);
}

function createSvgElement(name) {
	return document.createElementNS('http://www.w3.org/2000/svg', name);
}

function createText(data) {
	return document.createTextNode(data);
}

function createComment() {
	return document.createComment('');
}

function addListener(node, event, handler) {
	node.addEventListener(event, handler, false);
}

function removeListener(node, event, handler) {
	node.removeEventListener(event, handler, false);
}

function setAttribute(node, attribute, value) {
	node.setAttribute(attribute, value);
}

function setXlinkAttribute(node, attribute, value) {
	node.setAttributeNS('http://www.w3.org/1999/xlink', attribute, value);
}

function getBindingGroupValue(group) {
	var value = [];
	for (var i = 0; i < group.length; i += 1) {
		if (group[i].checked) value.push(group[i].__value);
	}
	return value;
}

function toNumber(value) {
	return value === '' ? undefined : +value;
}

function children (element) {
	return Array.from(element.childNodes);
}

function claimElement (nodes, name, attributes, svg) {
	for (var i = 0; i < nodes.length; i += 1) {
		var node = nodes[i];
		if (node.nodeName === name) {
			for (var j = 0; j < node.attributes.length; j += 1) {
				var attribute = node.attributes[j];
				if (!attributes[attribute.name]) node.removeAttribute(attribute.name);
			}
			return nodes.splice(i, 1)[0]; // TODO strip unwanted attributes
		}
	}

	return svg ? createSvgElement(name) : createElement(name);
}

function claimText (nodes, data) {
	for (var i = 0; i < nodes.length; i += 1) {
		var node = nodes[i];
		if (node.nodeType === 3) {
			node.data = data;
			return nodes.splice(i, 1)[0];
		}
	}

	return createText(data);
}

function linear(t) {
	return t;
}

function generateKeyframes(
	a,
	b,
	delta,
	duration,
	ease,
	fn,
	node,
	style
) {
	var id = '__svelte' + ~~(Math.random() * 1e9); // TODO make this more robust
	var keyframes = '@keyframes ' + id + '{\n';

	for (var p = 0; p <= 1; p += 16.666 / duration) {
		var t = a + delta * ease(p);
		keyframes += p * 100 + '%{' + fn(t) + '}\n';
	}

	keyframes += '100% {' + fn(b) + '}\n}';
	style.textContent += keyframes;

	document.head.appendChild(style);

	node.style.animation = (node.style.animation || '')
		.split(',')
		.filter(function(anim) {
			// when introing, discard old animations if there are any
			return anim && (delta < 0 || !/__svelte/.test(anim));
		})
		.concat(id + ' ' + duration + 'ms linear 1 forwards')
		.join(', ');
}

function wrapTransition(node, fn, params, intro, outgroup) {
	var obj = fn(node, params);
	var duration = obj.duration || 300;
	var ease = obj.easing || linear;
	var cssText;

	// TODO share <style> tag between all transitions?
	if (obj.css) {
		var style = document.createElement('style');
	}

	if (intro) {
		if (obj.css && obj.delay) {
			cssText = node.style.cssText;
			node.style.cssText += obj.css(0);
		}

		if (obj.tick) obj.tick(0);
	}

	return {
		t: intro ? 0 : 1,
		running: false,
		program: null,
		pending: null,
		run: function(intro, callback) {
			var program = {
				start: window.performance.now() + (obj.delay || 0),
				intro: intro,
				callback: callback
			};

			if (obj.delay) {
				this.pending = program;
			} else {
				this.start(program);
			}

			if (!this.running) {
				this.running = true;
				transitionManager.add(this);
			}
		},
		start: function(program) {
			program.a = this.t;
			program.b = program.intro ? 1 : 0;
			program.delta = program.b - program.a;
			program.duration = duration * Math.abs(program.b - program.a);
			program.end = program.start + program.duration;

			if (obj.css) {
				if (obj.delay) node.style.cssText = cssText;
				generateKeyframes(
					program.a,
					program.b,
					program.delta,
					program.duration,
					ease,
					obj.css,
					node,
					style
				);
			}

			this.program = program;
			this.pending = null;
		},
		update: function(now) {
			var program = this.program;
			if (!program) return;

			var p = now - program.start;
			this.t = program.a + program.delta * ease(p / program.duration);
			if (obj.tick) obj.tick(this.t);
		},
		done: function() {
			this.t = this.program.b;
			if (obj.tick) obj.tick(this.t);
			if (obj.css) document.head.removeChild(style);
			this.program.callback();
			this.program = null;
			this.running = !!this.pending;
		},
		abort: function() {
			if (obj.tick) obj.tick(1);
			if (obj.css) document.head.removeChild(style);
			this.program = this.pending = null;
			this.running = false;
		}
	};
}

var transitionManager = {
	running: false,
	transitions: [],
	bound: null,

	add: function(transition) {
		this.transitions.push(transition);

		if (!this.running) {
			this.running = true;
			this.next();
		}
	},

	next: function() {
		this.running = false;

		var now = window.performance.now();
		var i = this.transitions.length;

		while (i--) {
			var transition = this.transitions[i];

			if (transition.program && now >= transition.program.end) {
				transition.done();
			}

			if (transition.pending && now >= transition.pending.start) {
				transition.start(transition.pending);
			}

			if (transition.running) {
				transition.update(now);
				this.running = true;
			} else if (!transition.pending) {
				this.transitions.splice(i, 1);
			}
		}

		if (this.running) {
			requestAnimationFrame(this.bound || (this.bound = this.next.bind(this)));
		}
	}
};

function differs(a, b) {
	return a !== b || ((a && typeof a === 'object') || typeof a === 'function');
}

function dispatchObservers(component, group, newState, oldState) {
	for (var key in group) {
		if (!(key in newState)) continue;

		var newValue = newState[key];
		var oldValue = oldState[key];

		if (differs(newValue, oldValue)) {
			var callbacks = group[key];
			if (!callbacks) continue;

			for (var i = 0; i < callbacks.length; i += 1) {
				var callback = callbacks[i];
				if (callback.__calling) continue;

				callback.__calling = true;
				callback.call(component, newValue, oldValue);
				callback.__calling = false;
			}
		}
	}
}

function get(key) {
	return key ? this._state[key] : this._state;
}

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) {
		handlers[i].call(this, data);
	}
}

function observe(key, callback, options) {
	var group = options && options.defer
		? this._observers.post
		: this._observers.pre;

	(group[key] || (group[key] = [])).push(callback);

	if (!options || options.init !== false) {
		callback.__calling = true;
		callback.call(this, this._state[key]);
		callback.__calling = false;
	}

	return {
		cancel: function() {
			var index = group[key].indexOf(callback);
			if (~index) group[key].splice(index, 1);
		}
	};
}

function observeDev(key, callback, options) {
	var c = (key = '' + key).search(/[^\w]/);
	if (c > -1) {
		var message =
			'The first argument to component.observe(...) must be the name of a top-level property';
		if (c > 0)
			message += ", i.e. '" + key.slice(0, c) + "' rather than '" + key + "'";

		throw new Error(message);
	}

	return observe.call(this, key, callback, options);
}

function on(eventName, handler) {
	if (eventName === 'teardown') return this.on('destroy', 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 onDev(eventName, handler) {
	if (eventName === 'teardown') {
		console.warn(
			"Use component.on('destroy', ...) instead of component.on('teardown', ...) which has been deprecated and will be unsupported in Svelte 2"
		);
		return this.on('destroy', handler);
	}

	return on.call(this, eventName, handler);
}

function set(newState) {
	this._set(assign({}, newState));
	this._root._flush();
}

function _flush() {
	if (!this._renderHooks) return;

	while (this._renderHooks.length) {
		this._renderHooks.pop()();
	}
}

var proto = {
	get: get,
	fire: fire,
	observe: observe,
	on: on,
	set: set,
	_flush: _flush
};

var protoDev = {
	get: get,
	fire: fire,
	observe: observeDev,
	on: onDev,
	set: set,
	_flush: _flush
};

export { differs, dispatchObservers, get, fire, observe, observeDev, on, onDev, set, _flush, proto, protoDev, appendNode, insertNode, detachNode, detachBetween, destroyEach, createElement, createSvgElement, createText, createComment, addListener, removeListener, setAttribute, setXlinkAttribute, getBindingGroupValue, toNumber, children, claimElement, claimText, linear, generateKeyframes, wrapTransition, transitionManager, noop, assign };