JavaScript: fetch, realize asynchronous request

JavaScript: fetch(), realize asynchronous request

Fetch is a method of HTTP data request and an alternative to XMLHttpRequest. Fetch is not a further encapsulation of ajax, but native js. The Fetch function is native js and does not use the XMLHttpRequest object.

fetch

• parameter

  1. URL: request address
  2. option: configuration options, using setting methods, request headers, request body, etc.;

• demonstration

  fetch(URL,{
        
        
      method : 'POST',
      body : data,
      headers : {
        
        
          "ContentType" : "application/json"
      }
      // 其他配置
  })
      .then(response=>response.json())	//返回一个promise对象
      .then(data=>console.log(data))
      .catch(error=>console.log(error))
  

• Advanced version

• You can also new a Request object, and then pass in the fetch method after configuration

  let req = new Request(URL,{
        
        method : 'POST'});
  fetch(req)
      .then(response=>response.json())
  	.then(data=>console.log(data));