javascript - 从ajax数据设置App

Question

我有一个关于如何正确编写我的应用程序的一般性问题。我从服务器获取数据，然后我想开始设置对象如果可能的话，最好在全局范围内。在没有 async: false 的情况下如何管理(我读到这是一个不好的做法)？什么是正确的方法？

var people = {
   url: 'api/myapp/data.json'
   name: '',
   lastName: '',
   age: 0
}

var someFuncWithLastName(){
 //some use of the data that I got from the server
 //people.lastName suppose...after it got the correct data from the ajax res
}

//Get Data from server 
var getData = function() {
    $.ajax({
        method: 'GET',
        url: 'api/myapp/data.json',
        success: function(res){ 
           people = res 
           // res = { url:'api/myapp/data.json', name:'John', lastName:'Snow', age:34}
        },
        error: function (error) {
            console.log(error);
        }
    });
} 

Answer 1

Promise 是正确的方法(你永远不应该污染全局范围):

function someFuncWithLastName (){
  //some use of the data that I got from the server
  //people.lastName suppose...
  getDataForChart().then(data => {
     console.log(data);
  }
}

//Get Data from server 
var getDataForChart = function() {
    return $.ajax({
        method: 'GET',
        url: 'api/myapp/data.json',
    });
}

使用新的 es6 wait 语法，您甚至可以使这变得更容易:

function someFuncWithLastName() {
  //some use of the data that I got from the server
  //people.lastName suppose...
  const data = await getDataForChart();

  console.log(data);
}

//Get Data from server 
var getDataForChart = function() {
    return $.ajax({
        method: 'GET',
        url: 'api/myapp/data.json',
    });
}

如果不了解更多，就很难告诉你更多。您可以考虑使用类:

// Helper function for simulating an AJAX call
const delay = (ms) => new Promise(resolve => setTimeout(resolve, ms));

class Person {
  constructor(name, lastName) {
    this.name = name;
    this.lastName = lastName;
  }
  
  async getChartData() {
    console.log(`Making call to /api/myapp/data.json?${this.name}`);
    
    await delay(2000);
    
    return {some: 'a', sample: 'b', data: 'c'};
  }
  
  async getOtherData() {
    console.log(`Making call to /api/myapp/otherData.json?${this.name}`);
    
    await delay(3000);
    
    return {more: 'x', data: 'y'};
  }
}

const person = new Person('John', 'Doe');

// These do not block (Functionally almost identical to using Promise.all in an async function)
// person.getChartData().then(data => console.log('Data Returned: ', data));
// person.getOtherData().then(data => console.log('Data Returned: ', data));

async function main() {
  // These will "block" (Not really blocking, just waiting before continuing with the rest)
  console.log('== await each ==');
  const data = await person.getChartData();
  console.log(data);
  
  const otherData = await person.getOtherData();
  console.log(otherData);
  
  console.log('== Run concurrently ==');
  
  const [data2, otherData2] = await Promise.all([person.getChartData(), person.getOtherData()]);
  
  console.log('All data returned', data2, otherData2);
}

// Call the main function (This does not block the main thread)
main();