Merge branch 'master' into skip-coercion

debug/mangle.json

@@ -8,7 +8,8 @@
       "properties": {
         "regex": "^_",
         "reserved": [
-          "__REACT_DEVTOOLS_GLOBAL_HOOK__"
+          "__REACT_DEVTOOLS_GLOBAL_HOOK__",
+          "_renderers"
         ]
       }
     }

src/component.js

@@ -108,7 +108,7 @@ let q = [];
  * Asynchronously schedule a callback
  * @type {(cb) => void}
  */
-const defer = typeof Promise=='function' ? Promise.resolve().then.bind(Promise.resolve()) : setTimeout;
+const defer = typeof Promise=='function' ? Promise.prototype.then.bind(Promise.resolve()) : setTimeout;
 
 /*
  * The value of `Component.debounce` must asynchronously invoke the passed in callback. It is

src/diff/children.js

@@ -23,8 +23,8 @@ export function diffChildren(parentDom, newParentVNode, oldParentVNode, context,
 		nextDom, sibDom, focus,
 		childDom;
 
-	let newChildren = getVNodeChildren(newParentVNode);
-	let oldChildren = oldParentVNode==null || oldParentVNode==EMPTY_OBJ ? EMPTY_ARR : getVNodeChildren(oldParentVNode);
+	let newChildren = newParentVNode._children || toChildArray(newParentVNode.props.children, newParentVNode._children=[], coerceToVNode);
+	let oldChildren = oldParentVNode!=null && oldParentVNode!=EMPTY_OBJ && oldParentVNode._children || EMPTY_ARR;
 
 	let oldChildrenLength = oldChildren.length;
 
@@ -123,19 +123,6 @@ export function diffChildren(parentDom, newParentVNode, oldParentVNode, context,
 	for (i=oldChildren.length; i--; ) if (oldChildren[i]!=null) unmount(oldChildren[i], ancestorComponent);
 }
 
-/**
- * Get the children of a virtual node as a flat array
- * @param {import('../internal').VNode} vnode The virtual node to get the
- * children of
- * @returns {Array<import('../internal').VNode>} The virtual node's children
- */
-function getVNodeChildren(vnode) {
-	if (vnode._children==null) {
-		toChildArray(vnode.props.children, vnode._children=[], coerceToVNode);
-	}
-	return vnode._children;
-}
-
 /**
  * Flatten a virtual nodes children to a single dimensional array
  * @param {import('../index').ComponentChildren} children The unflattened

src/index.d.ts

@@ -99,8 +99,15 @@ declare namespace preact {
 		static displayName?: string;
 		static defaultProps?: any;
 		static contextType?: PreactContext<any>;
-		static getDerivedStateFromProps?<P, S>(props: P, state: S): Partial<S>;
-		static getDerivedStateFromError?<S>(error: any): Partial<S>;
+
+		// Static members cannot reference class type parameters. This is not
+		// supported in TypeScript. Reusing the same type arguments from `Component`
+		// will lead to an impossible state where one cannot satisfy the type
+		// constraint under no circumstances, see #1356.In general type arguments
+		// seem to be a bit buggy and not supported well at the time of this
+		// writing with TS 3.3.3333.
+		static getDerivedStateFromProps?(props: Readonly<object>, state: Readonly<object>): object;
+		static getDerivedStateFromError?(error: any): object;
 
 		state: Readonly<S>;
 		props: RenderableProps<P>;

test/ts/Component-test.tsx

@@ -97,6 +97,25 @@ class RandomChildrenComponent extends Component<RandomChildrenComponenProps> {
 	}
 }
 
+class StaticComponent extends Component<SimpleComponentProps, SimpleState> {
+	static getDerivedStateFromProps(props: SimpleComponentProps, state: SimpleState): Partial<SimpleState> {
+		return {
+			...props,
+			...state
+		}
+	}
+
+	static getDerivedStateFromError(err: Error) {
+		return {
+			name: err.message
+		};
+	}
+
+	render() {
+		return null;
+	}
+}
+
 describe("Component", () => {
 	const component = new SimpleComponent({ initialName: "da name" });