Apply some performance optimisation

packages/driver-dom/src/index.js

@@ -364,8 +364,8 @@ export function afterRender({ container }) {
 
 /**
  * Remove all children from node.
- * @NOTE: Fast path support in web.
+ * @NOTE: Optimization at web.
  */
 export function removeChildren(node) {
-  node.innerHTML = '';
+  node.textContent = '';
 }

packages/rax/src/hooks.js

@@ -1,7 +1,7 @@
 import Host from './vdom/host';
 import { scheduleEffect, flushEffect } from './vdom/scheduler';
 import { is } from './vdom/shallowEqual';
-import { isFunction } from './types';
+import {isFunction, isNull} from './types';
 import { invokeMinifiedError } from './error';
 
 function getCurrentInstance() {
@@ -22,7 +22,7 @@ function getCurrentRenderingInstance() {
 }
 
 function areInputsEqual(inputs, prevInputs) {
-  if (prevInputs === null || inputs.length !== prevInputs.length) {
+  if (isNull(prevInputs) || inputs.length !== prevInputs.length) {
     return false;
   }
 
@@ -198,7 +198,7 @@ export function useMemo(create, inputs) {
     hooks[hookID] = [create(), inputs];
   } else {
     const prevInputs = hooks[hookID][1];
-    if (inputs === null || !areInputsEqual(inputs, prevInputs)) {
+    if (isNull(inputs) || !areInputsEqual(inputs, prevInputs)) {
       hooks[hookID] = [create(), inputs];
     }
   }

packages/rax/src/types.js

@@ -1,3 +1,9 @@
+export const NULL = null;
+
+export function isNull(obj) {
+  return obj === NULL;
+}
+
 export function isFunction(obj) {
   return typeof obj === 'function';
 }

packages/rax/src/vdom/instantiateComponent.js

@@ -1,11 +1,11 @@
 import Host from './host';
-import { isString, isNumber, isObject, isArray } from '../types';
+import {isString, isNumber, isObject, isArray, isNull} from '../types';
 import { invokeMinifiedError } from '../error';
 
 function instantiateComponent(element) {
   let instance;
 
-  if (element === undefined || element === null || element === false || element === true) {
+  if (element === undefined || isNull(element) || element === false || element === true) {
     instance = new Host.Empty();
   } else if (isArray(element)) {
     instance = new Host.Fragment(element);

packages/rax/src/vdom/native.js

@@ -6,7 +6,7 @@ import getElementKeyName from './getElementKeyName';
 import Instance from './instance';
 import BaseComponent from './base';
 import toArray from './toArray';
-import { isFunction, isArray } from '../types';
+import {isFunction, isArray, isNull} from '../types';
 
 const STYLE = 'style';
 const CHILDREN = 'children';
@@ -345,7 +345,7 @@ class NativeComponent extends BaseComponent {
     // `driver.removeChildren` is optional driver protocol.
     let shouldRemoveAllChildren = Boolean(
       driver.removeChildren
-      && nextChildrenElements === null || nextChildrenElements && nextChildrenElements.length === 0
+      && isNull(nextChildrenElements) || nextChildrenElements && nextChildrenElements.length === 0
     );
 
     // Unmount children that are no longer present.

packages/rax/src/vdom/shallowEqual.js

@@ -1,4 +1,4 @@
-import { isObject } from '../types';
+import {isNull, isObject} from '../types';
 
 const hasOwnProperty = {}.hasOwnProperty;
 
@@ -28,7 +28,7 @@ export default function shallowEqual(objA, objB) {
     return true;
   }
 
-  if (!isObject(objA) || objA === null || !isObject(objB) || objB === null) {
+  if (!isObject(objA) || isNull(objA) || !isObject(objB) || isNull(objB)) {
     return false;
   }
 

packages/rax/src/vdom/shouldUpdateComponent.js

@@ -1,8 +1,8 @@
-import { isArray, isString, isNumber, isObject } from '../types';
+import {isArray, isString, isNumber, isObject, isNull} from '../types';
 
 function shouldUpdateComponent(prevElement, nextElement) {
-  let prevEmpty = prevElement === null;
-  let nextEmpty = nextElement === null;
+  let prevEmpty = isNull(prevElement);
+  let nextEmpty = isNull(nextElement);
   if (prevEmpty || nextEmpty) {
     return prevEmpty === nextEmpty;
   }