采用React编写小程序的Remax框架的编译流程解析(推荐)
作者：我的小树林
这篇文章主要介绍了采用React编写小程序的Remax框架的编译流程解析(推荐),本文通过实例代码给大家介绍的非常详细，对大家的学习或工作具有一定的参考借鉴价值，需要的朋友可以参考下
Remax是蚂蚁开源的一个用React来开发小程序的框架，采用运行时无语法限制的方案。整体研究下来主要分为三大部分：运行时原理、模板渲染原理、编译流程；看了下现有大部分文章主要集中在Reamx的运行时和模板渲染原理上，而对整个React代码编译为小程序的流程介绍目前还没有看到，本文即是来补充这个空白。
关于模板渲染原理看这篇文章：https://www.jb51.net/article/132635.htm
关于remax运行时原理看这篇文章：https://www.jb51.net/article/210293.htm
关于React自定义渲染器看这篇文章：https://www.jb51.net/article/198425.htm
Remax的基本结构：
1、remax-runtime 运行时，提供自定义渲染器、宿主组件的包装、以及由React组件到小程序的App、Page、Component的配置生成器
// 自定义渲染器
export { default as render } from './render';
// 由app.js到小程序App构造器的配置处理
export { default as createAppConfig } from './createAppConfig';
// 由React到小程序Page页面构造器的一系列适配处理
export { default as createPageConfig } from './createPageConfig';
// 由React组件到小程序自定义组件Component构造器的一系列适配处理
export { default as createComponentConfig } from './createComponentConfig';
//
export { default as createNativeComponent } from './createNativeComponent';
// 生成宿主组件，比如小程序原生提供的View、Button、Canvas等
export { default as createHostComponent } from './createHostComponent';
export { createPortal } from './ReactPortal';
export { RuntimeOptions, PluginDriver } from '@remax/framework-shared';
export * from './hooks';
import { ReactReconcilerInst } from './render';
export const unstable_batchedUpdates = ReactReconcilerInst.batchedUpdates;
export default {
unstable_batchedUpdates,
};
2、remax-wechat 小程序相关适配器
template模板相关，与模板相关的处理原则及原理可以看这个https://www.jb51.net/article/145552.htm
templates // 与渲染相关的模板
src/api 适配与微信小程序相关的各种全局api，有的进行了promisify化
import { promisify } from '@remax/framework-shared';
declare const wx: WechatMiniprogram.Wx;
export const canIUse = wx.canIUse;
export const base64ToArrayBuffer = wx.base64ToArrayBuffer;
export const arrayBufferToBase64 = wx.arrayBufferToBase64;
export const getSystemInfoSync = wx.getSystemInfoSync;
export const getSystemInfo = promisify(wx.getSystemInfo);
src/types/config.ts 与小程序的Page、App相关配置内容的适配处理
/** 页面配置文件 */
// reference: https://developers.weixin.qq.com/miniprogram/dev/reference/configuration/page.html
export interface PageConfig {
/**
* 默认值：#000000
* 导航栏背景颜色，如 #000000
*/
navigationBarBackgroundColor?: string;
/**
* 默认值：white
* 导航栏标题颜色，仅支持 black / white
*/
navigationBarTextStyle?: 'black' | 'white';
/** 全局配置文件 */
// reference: https://developers.weixin.qq.com/miniprogram/dev/reference/configuration/app.html
export interface AppConfig {
/**
* 页面路径列表
*/
pages: string[];
/**
* 全局的默认窗口表现
*/
window?: {
/**
* 默认值：#000000
* 导航栏背景颜色，如 #000000
*/
navigationBarBackgroundColor?: string;
/**
* 默认值: white
* 导航栏标题颜色，仅支持 black / white
*/
navigationBarTextStyle?: 'white' | 'black';
src/types/component.ts 微信内置组件相关的公共属性、事件等属性适配
import * as React from 'react';
/** 微信内置组件公共属性 */
// reference: https://developers.weixin.qq.com/miniprogram/dev/framework/view/component.html
export interface BaseProps {
/** 自定义属性: 组件上触发的事件时，会发送给事件处理函数 */
readonly dataset?: DOMStringMap;
/** 组件的唯一标示: 保持整个页面唯一 */
id?: string;
/** 组件的样式类: 在对应的 WXSS 中定义的样式类 */
className?: string;
/** 组件的内联样式: 可以动态设置的内联样式 */
style?: React.CSSProperties;
/** 组件是否显示: 所有组件默认显示 */
hidden?: boolean;
/** 动画对象: 由`wx.createAnimation`创建 */
animation?: Array<Record<string, any>>;
// reference: https://developers.weixin.qq.com/miniprogram/dev/framework/view/wxml/event.html
/** 点击时触发 */
onTap?: (event: TouchEvent) => void;
/** 点击时触发 */
onClick?: (event: TouchEvent) => void;
/** 手指触摸动作开始 */
onTouchStart?: (event: TouchEvent) => void;
src/hostComponents 针对微信小程序宿主组件的包装和适配；node.ts是将小程序相关属性适配到React的规范
export const alias = {
id: 'id',
className: 'class',
style: 'style',
animation: 'animation',
src: 'src',
loop: 'loop',
controls: 'controls',
poster: 'poster',
name: 'name',
author: 'author',
onError: 'binderror',
onPlay: 'bindplay',
onPause: 'bindpause',
onTimeUpdate: 'bindtimeupdate',
onEnded: 'bindended',
};
export const props = Object.values(alias);
各种组件也是利用createHostComponent生成
import * as React from 'react';
import { createHostComponent } from '@remax/runtime';
// 微信已不再维护
export const Audio: React.ComponentType = createHostComponent('audio');
createHostComponent生成React的Element
import * as React from 'react';
import { RuntimeOptions } from '@remax/framework-shared';
export default function createHostComponent<P = any>(name: string, component?: React.ComponentType<P>) {
if (component) {
return component;
}
const Component = React.forwardRef((props, ref: React.Ref<any>) => {
const { children = [] } = props;
let element = React.createElement(name, { ...props, ref }, children);
element = RuntimeOptions.get('pluginDriver').onCreateHostComponentElement(element) as React.DOMElement<any, any>;
return element;
});
return RuntimeOptions.get('pluginDriver').onCreateHostComponent(Component);
}
3、remax-macro 按照官方描述是基于babel-plugin-macros的宏；所谓宏是在编译时进行字符串的静态替换，而Javascript没有编译过程，babel实现宏的方式是在将代码编译为ast树之后，对ast语法树进行操作来替换原本的代码。详细文章可以看这里https://zhuanlan.zhihu.com/p/64346538；
remax这里是利用macro来进行一些宏的替换，比如useAppEvent和usePageEvent等，替换为从remax/runtime中进行引入
import { createMacro } from 'babel-plugin-macros';
import createHostComponentMacro from './createHostComponent';
import requirePluginComponentMacro from './requirePluginComponent';
import requirePluginMacro from './requirePlugin';
import usePageEventMacro from './usePageEvent';
import useAppEventMacro from './useAppEvent';
function remax({ references, state }: { references: { [name: string]: NodePath[] }; state: any }) {
references.createHostComponent?.forEach(path => createHostComponentMacro(path, state));
references.requirePluginComponent?.forEach(path => requirePluginComponentMacro(path, state));
references.requirePlugin?.forEach(path => requirePluginMacro(path));
const importer = slash(state.file.opts.filename);
Store.appEvents.delete(importer);
Store.pageEvents.delete(importer);
references.useAppEvent?.forEach(path => useAppEventMacro(path, state));
references.usePageEvent?.forEach(path => usePageEventMacro(path, state));
}
export declare function createHostComponent<P = any>(
name: string,
props: Array<string | [string, string]>
): React.ComponentType<P>;
export declare function requirePluginComponent<P = any>(pluginName: string): React.ComponentType<P>;
export declare function requirePlugin<P = any>(pluginName: string): P;
export declare function usePageEvent(eventName: PageEventName, callback: (...params: any[]) => any): void;
export declare function useAppEvent(eventName: AppEventName, callback: (...params: any[]) => any): void;
export default createMacro(remax);
import * as t from '@babel/types';
import { slash } from '@remax/shared';
import { NodePath } from '@babel/traverse';
import Store from '@remax/build-store';
import insertImportDeclaration from './utils/insertImportDeclaration';
const PACKAGE_NAME = '@remax/runtime';
const FUNCTION_NAME = 'useAppEvent';
function getArguments(callExpression: NodePath<t.CallExpression>, importer: string) {
const args = callExpression.node.arguments;
const eventName = args[0] as t.StringLiteral;
const callback = args[1];
Store.appEvents.set(importer, Store.appEvents.get(importer)?.add(eventName.value) ?? new Set([eventName.value]));
return [eventName, callback];
}
export default function useAppEvent(path: NodePath, state: any) {
const program = state.file.path;
const importer = slash(state.file.opts.filename);
const functionName = insertImportDeclaration(program, FUNCTION_NAME, PACKAGE_NAME);
const callExpression = path.findParent(p => t.isCallExpression(p)) as NodePath<t.CallExpression>;
const [eventName, callback] = getArguments(callExpression, importer);
callExpression.replaceWith(t.callExpression(t.identifier(functionName), [eventName, callback]));
}
个人感觉这个设计有些过于复杂，可能跟remax的设计有关，在remax/runtime中，useAppEvent实际从remax-framework-shared中导出；
不过也倒是让我学到了一种对代码修改的处理方式。
4、remax-cli remax的脚手架，整个remax工程，生成到小程序的编译流程也是在这里处理。
先来看一下一个作为Page的React文件是如何与小程序的原生Page构造器关联起来的。
假设原先页面代码是这个样子，
import * as React from 'react';
import { View, Text, Image } from 'remax/wechat';
import styles from './index.css';
export default () => {
return (
<View className={styles.app}>
<View className={styles.header}>
<Image
src="https://gw.alipayobjects.com/mdn/rms_b5fcc5/afts/img/A*OGyZSI087zkAAAAAAAAAAABkARQnAQ"
className={styles.logo}
alt="logo"
/>
<View className={styles.text}>
编辑 <Text className={styles.path}>src/pages/index/index.js</Text>开始
</View>
</View>
</View>
);
};
这部分处理在remax-cli/src/build/entries/PageEntries.ts代码中，可以看到这里是对源码进行了修改，引入了runtime中的createPageConfig函数来对齐React组件与小程序原生Page需要的属性，同时调用原生的Page构造器来实例化页面。
import * as path from 'path';
import VirtualEntry from './VirtualEntry';
export default class PageEntry extends VirtualEntry {
outputSource() {
return `
import { createPageConfig } from '@remax/runtime';
import Entry from './${path.basename(this.filename)}';
Page(createPageConfig(Entry, '${this.name}'));
`;
}
}
createPageConfig来负责将React组件挂载到remax自定义的渲染容器中，同时对小程序Page的各个生命周期与remax提供的各种hook进行关联
export default function createPageConfig(Page: React.ComponentType<any>, name: string) {
const app = getApp() as any;
const config: any = {
data: {
root: {
children: [],
},
modalRoot: {
children: [],
},
},
wrapperRef: React.createRef<any>(),
lifecycleCallback: {},
onLoad(this: any, query: any) {
const PageWrapper = createPageWrapper(Page, name);
this.pageId = generatePageId();
this.lifecycleCallback = {};
this.data = { // Page中定义的data实际是remax在内存中生成的一颗镜像树
root: {
children: [],
},
modalRoot: {
children: [],
},
};
this.query = query;
// 生成自定义渲染器需要定义的容器
this.container = new Container(this, 'root');
this.modalContainer = new Container(this, 'modalRoot');
// 这里生成页面级别的React组件
const pageElement = React.createElement(PageWrapper, {
page: this,
query,
modalContainer: this.modalContainer,
ref: this.wrapperRef,
});
if (app && app._mount) {
this.element = createPortal(pageElement, this.container, this.pageId);
app._mount(this);
} else {
// 调用自定义渲染器进行渲染
this.element = render(pageElement, this.container);
}
// 调用生命周期中的钩子函数
return this.callLifecycle(Lifecycle.load, query);
},
onUnload(this: any) {
this.callLifecycle(Lifecycle.unload);
this.unloaded = true;
this.container.clearUpdate();
app._unmount(this);
},
Container是按照React自定义渲染规范定义的根容器，最终是在applyUpdate方法中调用小程序原生的setData方法来更新渲染视图
applyUpdate() {
if (this.stopUpdate || this.updateQueue.length === 0) {
return;
}
const startTime = new Date().getTime();
if (typeof this.context.$spliceData === 'function') {
let $batchedUpdates = (callback: () => void) => {
callback();
};
if (typeof this.context.$batchedUpdates === 'function') {
$batchedUpdates = this.context.$batchedUpdates;
}
$batchedUpdates(() => {
this.updateQueue.map((update, index) => {
let callback = undefined;
if (index + 1 === this.updateQueue.length) {
callback = () => {
nativeEffector.run();
/* istanbul ignore next */
if (RuntimeOptions.get('debug')) {
console.log(`setData => 回调时间：${new Date().getTime() - startTime}ms`);
}
};
}
if (update.type === 'splice') {
this.context.$spliceData(
{
[this.normalizeUpdatePath([...update.path, 'children'])]: [
update.start,
update.deleteCount,
...update.items,
],
},
callback
);
}
if (update.type === 'set') {
this.context.setData(
{
[this.normalizeUpdatePath([...update.path, update.name])]: update.value,
},
callback
);
}
});
});
this.updateQueue = [];
return;
}
const updatePayload = this.updateQueue.reduce<{ [key: string]: any }>((acc, update) => {
if (update.node.isDeleted()) {
return acc;
}
if (update.type === 'splice') {
acc[this.normalizeUpdatePath([...update.path, 'nodes', update.id.toString()])] = update.items[0] || null;
if (update.children) {
acc[this.normalizeUpdatePath([...update.path, 'children'])] = (update.children || []).map(c => c.id);
}
} else {
acc[this.normalizeUpdatePath([...update.path, update.name])] = update.value;
}
return acc;
}, {});
// 更新渲染视图
this.context.setData(updatePayload, () => {
nativeEffector.run();
/* istanbul ignore next */
if (RuntimeOptions.get('debug')) {
console.log(`setData => 回调时间：${new Date().getTime() - startTime}ms`, updatePayload);
}
});
this.updateQueue = [];
}
而对于容器的更新是在render文件中的render方法进行的，
function getPublicRootInstance(container: ReactReconciler.FiberRoot) {
const containerFiber = container.current;
if (!containerFiber.child) {
return null;
}
return containerFiber.child.stateNode;
}
export default function render(rootElement: React.ReactElement | null, container: Container | AppContainer) {
// Create a root Container if it doesnt exist
if (!container._rootContainer) {
container._rootContainer = ReactReconcilerInst.createContainer(container, false, false);
}
ReactReconcilerInst.updateContainer(rootElement, container._rootContainer, null, () => {
// ignore
});
return getPublicRootInstance(container._rootContainer);
}
另外这里渲染的组件，其实也是经过了createPageWrapper包装了一层，主要是为了处理一些forward-ref相关操作。
现在已经把页面级别的React组件与小程序原生Page关联起来了。
对于Component的处理与这个类似，可以看remax-cli/src/build/entries/ComponentEntry.ts文件
import * as path from 'path';
import VirtualEntry from './VirtualEntry';
export default class ComponentEntry extends VirtualEntry {
outputSource() {
return `
import { createComponentConfig } from '@remax/runtime';
import Entry from './${path.basename(this.filename)}';
Component(createComponentConfig(Entry));
`;
}
}
那么对于普通的组件，remax会把他们编译称为自定义组件，小程序的自定义组件是由json wxml wxss js组成，由React组件到这些文件的处理过程在remax-cli/src/build/webpack/plugins/ComponentAsset中处理，生成wxml、wxss和js文件
export default class ComponentAssetPlugin {
builder: Builder;
cache: SourceCache = new SourceCache();
constructor(builder: Builder) {
this.builder = builder;
}
apply(compiler: Compiler) {
compiler.hooks.emit.tapAsync(PLUGIN_NAME, async (compilation, callback) => {
const { options, api } = this.builder;
const meta = api.getMeta();
const { entries } = this.builder.entryCollection;
await Promise.all(
Array.from(entries.values()).map(async component => {
if (!(component instanceof ComponentEntry)) {
return Promise.resolve();
}
const chunk = compilation.chunks.find(c => {
return c.name === component.name;
});
const modules = [...getModules(chunk), component.filename];
let templatePromise;
if (options.turboRenders) {
// turbo page
templatePromise = createTurboTemplate(this.builder.api, options, component, modules, meta, compilation);
} else {
templatePromise = createTemplate(component, options, meta, compilation, this.cache);
}
await Promise.all([
await templatePromise,
await createManifest(this.builder, component, compilation, this.cache),
]);
})
);
callback();
});
}
}
而Page的一系列文件在remax-cli/src/build/webpack/plugins/PageAsset中进行处理，同时在createMainifest中会分析Page与自定义组件之间的依赖关系，自动生成usingComponents的关联关系。
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