The problem of passing values between javascript functions?

question: the ajax request initiated within a function will get a code, so as a b function, how to get the return value (code) of a function? The b function is triggered by other events.

Front-end function javascript

Apr.22,2021

var ajaxCode;
function a() {
    ajax({
        success: function(data){
            ajaxCode = data.code;
        }
    })
}

function b(){
    console.log(ajaxCode);
}

$('button').trigger('EventName',b);

this question should have been finished a long time ago. There are only three common ways of implementation:

use the traditional callback function callback
use Promise
use the event mechanism trigger on

I'm not familiar with the RxJs mentioned by others. At first glance, class Promise, is a good way to synchronize asynchronous programming.

function a( callBack ){
    $.ajax({ 
        url: "xxxxxxx",  
        success: function(data){
           if(data){
               return callBack&& callBack(data)
           }
        }
    })
}

function b(){
    a(function(data){
        //b
    })
}

this ensures that when the b event is triggered, the value of an is Synchronize. It's not going to happen that if you don't get the value of a, you have to do what b wants to do.

use promise

function a(){
  return ajax({...})
}

function b(){
  a().then(res=>{
    // res 
  })
}

it's OK to write on the second floor, and the one on the first floor can only be used for Synchronize, otherwise

use rxjs

rxjs is very suitable for such a scenario. Learn about

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