[IMP] component: disallow calling hooks outside of setup

(and constructor)

Doing so could cause strange and difficult bugs

src/component/component_node.ts

@@ -15,7 +15,10 @@ import { STATUS } from "./status";
 
 let currentNode: ComponentNode | null = null;
 
-export function getCurrent(): ComponentNode | null {
+export function getCurrent(): ComponentNode {
+  if (!currentNode) {
+    throw new Error("No active component (a hook function should only be called in 'setup')");
+  }
   return currentNode;
 }
 
@@ -108,6 +111,7 @@ export class ComponentNode<P = any, E = any> implements VNode<ComponentNode<P, E
     this.component = new C(props, env, this) as any;
     this.renderFn = app.getTemplate(C.template).bind(this.component, this.component, this);
     this.component.setup();
+    currentNode = null;
   }
 
   mountComponent(target: any, options?: MountOptions) {

src/component/lifecycle_hooks.ts

@@ -6,42 +6,42 @@ import { nodeErrorHandlers } from "./error_handling";
 // -----------------------------------------------------------------------------
 
 export function onWillStart(fn: () => Promise<void> | void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   node.willStart.push(fn.bind(node.component));
 }
 
 export function onWillUpdateProps(fn: (nextProps: any) => Promise<void> | void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   node.willUpdateProps.push(fn.bind(node.component));
 }
 
 export function onMounted(fn: () => void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   node.mounted.push(fn.bind(node.component));
 }
 
 export function onWillPatch(fn: () => Promise<void> | any | void) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   node.willPatch.unshift(fn.bind(node.component));
 }
 
 export function onPatched(fn: () => void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   node.patched.push(fn.bind(node.component));
 }
 
 export function onWillUnmount(fn: () => Promise<void> | void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   node.willUnmount.unshift(fn.bind(node.component));
 }
 
 export function onWillDestroy(fn: () => Promise<void> | void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   node.willDestroy.push(fn.bind(node.component));
 }
 
 export function onWillRender(fn: () => void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   const renderFn = node.renderFn;
   node.renderFn = () => {
     fn.call(node.component);
@@ -50,7 +50,7 @@ export function onWillRender(fn: () => void | any) {
 }
 
 export function onRendered(fn: () => void | any) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   const renderFn = node.renderFn;
   node.renderFn = () => {
     const result = renderFn();
@@ -61,7 +61,7 @@ export function onRendered(fn: () => void | any) {
 
 type OnErrorCallback = (error: any) => void | any;
 export function onError(callback: OnErrorCallback) {
-  const node = getCurrent()!;
+  const node = getCurrent();
   let handlers = nodeErrorHandlers.get(node);
   if (!handlers) {
     handlers = [];