how to use chained calls to promise when encountering asynchronous code across files?
I now write WeChat Mini Programs, calling wx.login,wx.getUserInfo in app.js and returning token and uid interfaces from my server.
but in a subpage, you need to get the uid returned in app.js before you can request the request of the current page again. Because it is cross-file, how to write this string of chained calls to promise?
var app=getApp ();
console.info (app.uid,app.token);
is it similar to this that only one call is made and all other calls are cached
var getUid = (function(){
var uid = null;
var flag = true;
var p = null;
return function(){
if(!uid){
if(flag){
flag = false;
//
p = new Promise(function(resolve){
setTimeout(function(){
resolve(uid=123);
},2000)
})
}
return p
}else{
return Promise.resolve(uid);
}
}
}());
getUid().then(function(v){
console.log(v)//2 123
})
getUid().then(function(v){
console.log(v)//2 123
})
setTimeout(function(){
getUid().then(function(v){
console.log(v)//5 123
})
},5000)event notification mechanism can be used. In your case, publish / subscribe mode is suitable.
you can refer to this article: https://aotu.io/notes/2017/01.
take the uid should be an asynchronous, package a promise, and then execute request
how to solve this problem
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