Proxy 对小程序异步调用进行封装的实现策略

function wxPromisify(fn) {

    return async function(args) {

        return new Promise((resolve, reject) => {

            fn({

                ...(args || {}),

                success: res => resolve(res),

                fail: err => reject(err)

            });

        });

    };

}

export function toAsync(names) {

    return (names || [])

        .map(name => (

            {

                name,

                member: wx[name]

            }

        ))

        .filter(t => typeof t.member === "function")

        .reduce((r, t) => {

            r[t.name] = wxPromisify(wx[t.name]);

            return r;

        }, {});

}

// pages/somepage/somepage.jsimport { toAsync } = require("../../utils/async");

// ...const awx = toAsync(["login", "request"]);await awx.login();await awx.request({...});

// utils/asyncjsfunction wxPromisify(fn) { ... }  

 // 前面已经定义过了export function asyncProxy(target) {   

 return new Proxy(target, {      

      cache: {},     

      get(it, prop) {      

          const aFn = this.cache[prop];  

          if (aFn) { return aFn; } 

          const v = it[prop];     

                if (typeof v !== "function") {         

                      return v;

            }           

            return this.cache[prop] = wxPromisify(v);

        }

    });

}

// app.jsimport { asyncProxy } from "./utils/async";

App({    onLaunch: function() {

        wx.awx = asyncProxy(wx);        // ....

    }

})

// pages/somepage/somepage// ...const { awx } = wx;await awx.login();await awx.request({...});

awx.login();

   ^^^^^^   get(wx, "login")