simplify streams, lint docs

stream/stream.js

@@ -0,0 +1,115 @@
+"use strict"
+
+var guid = 0, noop = function() {}, HALT = {}
+function createStream() {
+	function stream() {
+		if (arguments.length > 0 && arguments[0] !== HALT) updateStream(stream, arguments[0])
+		return stream._state.value
+	}
+	initStream(stream)
+
+	if (arguments.length > 0 && arguments[0] !== HALT) updateStream(stream, arguments[0])
+
+	return stream
+}
+function initStream(stream) {
+	stream.constructor = createStream
+	stream._state = {id: guid++, value: undefined, state: 0, derive: undefined, recover: undefined, deps: {}, parents: [], endStream: undefined}
+	stream.map = stream["fantasy-land/map"] = map, stream["fantasy-land/ap"] = ap, stream["fantasy-land/of"] = createStream
+	stream.valueOf = valueOf, stream.toJSON = toJSON, stream.toString = valueOf
+
+	Object.defineProperties(stream, {
+		end: {get: function() {
+			if (!stream._state.endStream) {
+				var endStream = createStream()
+				endStream.map(function(value) {
+					if (value === true) unregisterStream(stream), unregisterStream(endStream)
+					return value
+				})
+				stream._state.endStream = endStream
+			}
+			return stream._state.endStream
+		}}
+	})
+}
+function updateStream(stream, value) {
+	updateState(stream, value)
+	for (var id in stream._state.deps) updateDependency(stream._state.deps[id], false)
+	finalize(stream)
+}
+function updateState(stream, value) {
+	stream._state.value = value
+	stream._state.changed = true
+	if (stream._state.state !== 2) stream._state.state = 1
+}
+function updateDependency(stream, mustSync) {
+	var state = stream._state, parents = state.parents
+	if (parents.length > 0 && parents.filter(active).length === parents.length && (mustSync || parents.filter(changed).length > 0)) {
+		var value = stream._state.derive()
+		if (value === HALT) return false
+		updateState(stream, value)
+	}
+}
+function finalize(stream) {
+	stream._state.changed = false
+	for (var id in stream._state.deps) stream._state.deps[id]._state.changed = false
+}
+
+function combine(fn, streams) {
+	if (streams.length > streams.filter(valid).length) throw new Error("Ensure that each item passed to m.prop.combine/m.prop.merge is a stream")
+	return initDependency(createStream(), streams, function() {
+		return fn.apply(this, streams.concat([streams.filter(changed)]))
+	})
+}
+
+function initDependency(dep, streams, derive) {
+	var state = dep._state
+	state.derive = derive
+	state.parents = streams.filter(notEnded)
+
+	registerDependency(dep, state.parents)
+	updateDependency(dep, true)
+
+	return dep
+}
+function registerDependency(stream, parents) {
+	for (var i = 0; i < parents.length; i++) {
+		parents[i]._state.deps[stream._state.id] = stream
+		registerDependency(stream, parents[i]._state.parents)
+	}
+}
+function unregisterStream(stream) {
+	for (var i = 0; i < stream._state.parents.length; i++) {
+		var parent = stream._state.parents[i]
+		delete parent._state.deps[stream._state.id]
+	}
+	for (var id in stream._state.deps) {
+		var dependent = stream._state.deps[id]
+		var index = dependent._state.parents.indexOf(stream)
+		if (index > -1) dependent._state.parents.splice(index, 1)
+	}
+	stream._state.state = 2 //ended
+	stream._state.deps = {}
+}
+
+function map(fn) {return combine(function(stream) {return fn(stream())}, [this])}
+function ap(stream) {return combine(function(s1, s2) {return s1()(s2())}, [stream, this])}
+function valueOf() {return this._state.value}
+function toJSON() {return this._state.value != null && typeof this._state.value.toJSON === "function" ? this._state.value.toJSON() : this._state.value}
+
+function valid(stream) {return stream._state }
+function active(stream) {return stream._state.state === 1}
+function changed(stream) {return stream._state.changed}
+function notEnded(stream) {return stream._state.state !== 2}
+
+function merge(streams) {
+	return combine(function() {
+		return streams.map(function(s) {return s()})
+	}, streams)
+}
+createStream["fantasy-land/of"] = createStream
+createStream.merge = merge
+createStream.combine = combine
+createStream.HALT = HALT
+
+module.exports = createStream