Component({
 lifetimes: {
 attached() {
 Object.defineProperty(this, 'isComponent', {
 enumerable: true,
 get() { return true },
 });
 },
 },
});

// page.js
Page({
 data: {
 showChild2: false,
 },
 onChild1Attached() {
 this.setData({ showChild2: true });
 },
});

<!-- page.wxml -->
<child1 bind:attached="onChild1Attached"></child1>
<child2 wx:if="{{ showChild2 }}"></child2>

// child1.js
Component({
 lifetimes: {
 attached() {
 this.triggerEvent('attached');
 },
 },
});

<!-- child1.wxml -->
<view>child1</view>

// child2.js
Component({
 lifetimes: {
 attached() {
 Object.defineProperty(this, 'isComponent', {
 enumerable: true,
 get() { return true },
 });
 },
 },
});

<!-- child2.wxml -->
<view>child2</view>

// socket.js
Component({
 lifetimes: {
 ready() {
 this.getSocketConfig().then(config => {
 this.ws = wx.connectSocket(config);
 this.ws.onMessage(msg => {
 const data = JSON.parse(msg.data);
 this.onReceiveMessage(data);
 });
 });
 },
 detached() {
 this.ws && this.ws.close({});
 },
 },
 methods: {
 getSocketConfig() {
 // 从服务器请求 socket 连接配置
 return new Promise(() => {});
 },
 onReceiveMessage(data) {
 event.emit('message', data);
 },
 },
});

// page.js
Page({
 data: {
 showChild: true,
 },
 onLoad() {
 this.setData({ showChild: false });
 },
});

<!-- page.wxml -->
<child wx:if="{{ showChild }}" />

// child.js
Component({
 lifetimes: {
 created() {
 console.log('created');
 },
 attached() {
 console.log('attached');
 },
 ready() {
 console.log('ready');
 },
 detached() {
 console.log('detached');
 }
 },
});