// app.js 启动文件
App({
 globalData: {
  isLogin: false,
  userInfo: null,
  networkError: false,
  networkType: 'none'
 }
})

// test.js
const app = getApp();
const commonParams = app.globalData.isLogin;

// 存储-异步
swan.setStorage({
 key: 'key',
 data: 'value'
});
// 存储-同步
swan.setStorageSync('key', 'value');

// 获取-异步
swan.getStorage({
 key: 'key',
 success: function (res) {
  console.log(res.data);
 },
 fail: function (err) {
  console.log('错误码：' + err.errCode);
  console.log('错误信息：' + err.errMsg);
 }
});

// 获取-同步
const result = swan.getStorageSync('key');

// event.js 事件中心

class Event {
 on(event, fn, ctx) {
  if (typeof fn !== 'function') {
   console.error('fn must be a function');
   return;
  }

  this._stores = this._stores || {};
  (this._stores[event] = this._stores[event] || []).push({
   cb: fn,
   ctx: ctx
  });
 }
 emit(event, ...args) {
  this._stores = this._stores || {};
  let store = this._stores[event];
  if (store) {
   store = store.slice(0);
   for (let i = 0, len = store.length; i < len; i++) {
    store[i].cb.apply(store[i].ctx, args);
   }
  }
 }
 off(event, fn) {
  this._stores = this._stores || {};
  // all
  if (!arguments.length) {
   this._stores = {};
   return;
  }
  // specific event
  let store = this._stores[event];
  if (!store) {
   return;
  }
  // remove all handlers
  if (arguments.length === 1) {
   delete this._stores[event];
   return;
  }
  // remove specific handler
  let cb;
  for (let i = 0, len = store.length; i < len; i++) {
   cb = store[i].cb;
   if (cb === fn) {
    store.splice(i, 1);
    break;
   }
  }
  return;
 }
}

module.exports = Event;

// app.js
import Event from './utils/event';

App({
 event: new Event()
})

// view.js 阅读页进行订阅

Page({
 // 页面在回退时，会调用onShow方法
 onShow() {
  // 支付成功的回调，调起下载弹层
  app.event.on('afterPaySuccess', this.afterPaySuccess, this);
 },
 afterPaySuccess(e) {
  // ....业务逻辑
 }
})

// paySuccess.js

const app = getApp();

app.event.emit('afterPaySuccess', {
 docId: this.data.tradeInfo.docId,
 triggerFrom: 'docCashierBack'
});