如何在 Angular.js 中链接 .then 函数和回调成功函数 [英] How to chain .then functions and callback success function in Angular.js

问题描述

我正在尝试链接嵌套的 .then 函数并调用成功函数，但回调是在开始时调用.

I'm trying to chain nested .then functions and call the success functions, but call back is calling in the starting itself.

//public method fn
function fn(callback) {
//calling the 1st API request
fn1()
  .then(function(response) {
    //2nd API request function
    call1(response);
  }, function(error) {
    return $q.reject({
    responseStatus: error.status
  });

  })
  // Returning response
  .then(function(response) {
    callback({
    responseStatus: 200
    });
  }, function(error) {
    callback({
      responseStatus: 500
    });
  });
}

function call1(response) {
  //2nd API
  fn2()
    .then(function(response) {
     //3rd API request function
        call2(response);
      }, function(error) {
        return $q.reject({
        responseStatus: error.status
      });
    });
}


function call2(response) {
  //3rd API request 
  fn3()
    .then(function(response) {
        return lastfunction();
      //here i need to callback the success  response status
      }, function(error) {
        return $q.reject({
        responseStatus: error.status
      });
    });
}


function fn1(){
 //some code 
 }
function fn2(){
//some code 
}
function fn3(){
//some code 
}

//Controller

//i will show response status callback here

if(response.status ==200){
  show output;
 }
 else{
  //response 500
  show errors;
  }

基本上我需要在所有服务调用成功时将200"响应状态回调到其他控制器，即使一个请求失败，我也需要发送500".用我的代码'响应状态'200'正在调用第一个 .then 函数本身.我想将此服务调用称为 que

Basically i need to callback "200" response status to other controller on all service calls are successful and even if one request is failed i need to sent "500". with my code 'response status '200' is calling with the first .then function itself. I want to call this service calls as que

任何帮助将不胜感激.

推荐答案

你的 { responseStatus: x } 对象的存在仅仅是为了流量控制，自然可以提供fn()返回的promise的成功路径和错误路径；

Your { responseStatus: x } object exists solely for the purpose of flow control, which can be provided naturally by the success path and error path of a promise returned by fn();

此外，使用 Promise 时，无需将回调传递给 fn() - 实际上这样做被认为是不好的做法.

Also, with promises, there's no need to pass a callback to fn() - indeed it is considered bad practice to do so.

首先，

• 彻底清除回调
• 从每个低级函数返回一个承诺
• 简化成功链
• 清除不必要的错误处理程序

function fn() {
    return fn1().then(call1);
}
function call1() {
    return fn2().then(call2);
}
function call2() {
    return fn3().then(lastfunction);
}
function fn1() {
    //some code that returns a promise
}
function fn2() {
    //some code that returns a promise
}
function fn3() {
    //some code that returns a promise
}

然后，调用如下:

fn().then(function(response) {
    // success callback (your "200" condition)
    // show output;
}).catch(function(error) {
    // error callback (your "500" condition)
    // show error;
});

response var 将是 lastfunction() 传递的任何内容.如果您希望 response 成为 fn1()、fn2()、fn3 所交付内容的某种聚合，您会遇到问题() 还没有被 lastfunction() 传递.该问题在此处.

The response var will be whatever lastfunction() delivered. You have an issue if you want response to be some aggregation of what is delivered by fn1(), fn2(), fn3() that is not already delivered by lastfunction(). That issue is comprehensively addressed here.

error var 将是执行fn() 过程中第一个发生的Error，不会丢失信息；error.message 和 error.status(如果存在)可以被读取/显示.

The error var will be the first Error to occur in the course of executing fn(), with no loss of information; error.message and error.status (if it exists) can be read/displayed.

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