[WIP] New context API

src/create-context.js

@@ -0,0 +1,64 @@
+import { Component } from "./component";
+import { extendComponent } from "./util";
+
+/**
+ *
+ * @param {string} key
+ */
+export function createContext(key) {
+	/** Provider Component class.
+	 *	prop `value` is provided to every corresponding `Consumer` component.
+	 *	@public
+	 *
+	 */
+	function Provider(props, context) {
+		Component.call(this, props, context);
+
+		this.c = [];
+	}
+
+	extendComponent(Provider.prototype, {
+		s(subscriber) {
+			this.c.push(subscriber);
+			subscriber(this.props.value);
+		},
+
+		getChildContext() {
+			return { [key]: this.s };
+		},
+
+		componentWillReceiveProps(nextProps) {
+			if (!Object.is(this.props.value, nextProps.value)) {
+				this.c.forEach(subscriber => {
+					subscriber(nextProps.value);
+				});
+			}
+		},
+
+		render() {
+			return this.props.children;
+		}
+	});
+
+  /**  Consumer Component class.
+	 *	`children` must be a function that accepts the value from the `Consumer`'s
+	 		corresponding `Provider` component.
+	 *	@public
+	 *
+	 */
+	function Consumer(props, context) {
+		Component.call(this, props, context);
+
+		context[key](value => {
+			this.setState({ value });
+		});
+	}
+
+	extendComponent(Consumer.prototype, {
+		render() {
+			return this.props.children(this.state.value);
+		}
+	});
+
+	return { Provider, Consumer };
+}

src/preact.js

@@ -1,6 +1,7 @@
 import { h, h as createElement } from './h';
 import { cloneElement } from './clone-element';
 import { Component } from './component';
+import { createContext } from './create-context';
 import { render } from './render';
 import { rerender } from './render-queue';
 import options from './options';
@@ -10,6 +11,7 @@ export default {
 	createElement,
 	cloneElement,
 	Component,
+	createContext,
 	render,
 	rerender,
 	options
@@ -20,6 +22,7 @@ export {
 	createElement,
 	cloneElement,
 	Component,
+	createContext,
 	render,
 	rerender,
 	options

src/util.js

@@ -1,3 +1,5 @@
+import {Component} from './component';
+
 /**
  *  Copy all properties from `props` onto `obj`.
  *  @param {Object} obj		Object onto which properties should be copied.
@@ -18,3 +20,16 @@ export function extend(obj, props) {
  * @param {Function} callback
  */
 export const defer = typeof Promise=='function' ? Promise.resolve().then.bind(Promise.resolve()) : setTimeout;
+
+/**
+ * Extend an object from `Component`.
+ * @param {Object} obj    Object onto `Component` should be applied to.
+ * @param {Object} props	Object from which to copy properties.
+ * @private
+ */
+export function extendComponent(obj, props) {
+	obj = Object.create(Component.prototype);
+	obj.constructor = Component;
+	extend(obj, props);
+}
+