'set' on proxy: trap returned falsish for property

https://stackoverflow.com/questions/59187284/is-there-a-reason-why-this-proxy-always-throws-set-on-proxy-trap-returned-fal

https://github.com/GoogleChrome/proxy-polyfill/issues/20

简单来说就是你的proxy set方法最后要返回true，不管何种情况没返回true都会报这个错，实际这个问题的产生似乎都是在'use strict'模式下

const p = new Proxy({}, {
  set: function(target, prop, value, receiver) {
    //....
    //.....
    return true;  //proxy handler返回true
  }
})