1. Installation

1. Install npm install Axios using npm --save
2. Install bower install Axios with bower --save
3. Introduce <script src="https://unpkg.com/axios/dist/axios.min.js"></script>directly using cdn

2. Examples

1. Send a GET request

//Send a request with a given ID
axios.get('/user?ID=12345')
  .then(function(response){
    console.log(response);
  })
  .catch(function(err){
    console.log(err);
  });
//The above request can also be sent in this way
axios.get('/user',{
  params:{
    ID:12345
  }
})
.then(function(response){
  console.log(response);
})
.catch(function(err){
  console.log(err);
});

2. Send a POST request

axios.post('/user',{
  firstName:'Fred',
  lastName:'Flintstone'
})
.then(function(res){
  console.log(res);
})
.catch(function(err){
  console.log(err);
});

3. Concurrent multiple requests at once

function getUserAccount(){
  return axios.get('/user/12345');
}
function getUserPermissions(){
  return axios.get('/user/12345/permissions');
}
axios.all([getUserAccount(),getUserPermissions()])
  .then(axios.spread(function(acct,perms){
    //This function is triggered when both requests are completed, and the two parameters represent the returned results
  }))

III. API of axios

(1) axios can send requests by config

1, axios(config)

//Send a `POST`request
axios({
    method:"POST",
    url:'/user/12345',
    data:{
        firstName:"Fred",
        lastName:"Flintstone"
    }
});

2, axios(url[,config])

//Send a `GET` request (default request mode)
axios('/user/12345');

(2) Alias for the mode of request, which provides a convenient alias for all supported modes of request

axios.request(config);

axios.get(url[,config]);

axios.delete(url[,config]);

axios.head(url[,config]);

axios.post(url[,data[,config]]);

axios.put(url[,data[,config]])

axios.patch(url[,data[,config]])

• Note: When using the alias method, the parameters url,method,data do not need to be declared in the configuration

(3) Concurrent requests, which are auxiliary functions to help process concurrent requests

//iterable is an iterative parameter such as an array
axios.all(iterable)
//callback will not execute until all requests are completed
axios.spread(callback)

(4) Create an axios instance and customize its configuration

1, axios.create([config])

var instance = axios.create({
  baseURL:"https://some-domain.com/api/",
  timeout:1000,
  headers: {'X-Custom-Header':'foobar'}
});

2. Method of Instance

• Here's the Instance method, noting that the defined configuration merges with the configuration of the instance created using create

axios#request(config)

axios#get(url[,config])

axios#delete(url[,config])

axios#head(url[,config])

axios#post(url[,data[,config]])

axios#put(url[,data[,config]])

axios#patch(url[,data[,config]])

4. Configuration of Requests (request config)

• The following are the configuration options for the request, only the url option is required, and if the method option is undefined, it will send the request GET by default

{
  //`url` is the requested server address
  url:'/user',
  //`method` is how resources are requested
  method:'get'//default
  //If `url` is not an absolute address, `baseURL` will be added before `url`
  //Setting `baseURL'is convenient when `url' is a relative address
  baseURL:'https://some-domain.com/api/',
  //The `transformRequest` option allows us to make some changes to the requested data before the request is sent to the server
  //This option only applies to the following request methods: `put/post/patch`
  //The last function in the array must return a string, -an `ArrayBuffer` or `Stream`
  transformRequest:[function(data){
    //Change the data here to suit your needs
    return data;
  }],
  //The `transformResponse` option allows us to make changes to the data before it is transferred to the `then/catch` method
  transformResponse:[function(data){
    //Change the data here to suit your needs
    return data;
  }],
  //`headers` option is custom request header information that needs to be sent
  headers: {'X-Requested-With':'XMLHttpRequest'},
  //`params` option is the request parameter to be sent with the request - General link after URL
  //His type must be either a pure object or a URLSearchParams object
  params: {
    ID:12345
  },
  //`paramsSerializer` is an optional function designed to serialize parameters (params)
  //For example (https://www.npmjs.com/package/qs,http://api.jquery.com/jquery.param)
  paramsSerializer: function(params){
    return Qs.stringify(params,{arrayFormat:'brackets'})
  },
  //`data` option is data that needs to be sent as a requester
  //This option only applies to methods: `put/post/patch`
  //dada must be one of several types when the `transformRequest'option is not set
  //string/plain/object/ArrayBuffer/ArrayBufferView/URLSearchParams
  //Browser only: FormData/File/Bold
  //Only node:Stream
  data {
    firstName:"Fred"
  },
  //The `timeout` option defines the number of milliseconds of delay that a request is made
  //If the request takes longer than the delay, the request is terminated

  timeout:1000,
  //The `withCredentails'option indicates whether it is a cross-domain request?

  withCredentials:false,//default
  //`adapter`adapter option allows custom processing of requests, which makes testing easy
  //Returns a promise and provides a validation return
  adapter: function(config){
    /*..........*/
  },
  //`auth` Indicates that HTTP-based authentication should be used and provides a certificate
  //This sets an authorization header and overrides the Authorization header information you set in the header
  auth: {
    username:"zhangsan",
    password: "s00sdkf"
  },
  //Format of returned data
  //The options are arraybuffer,blob,document,json,text,stream,
  responseType:'json',//default
  //
  xsrfCookieName: 'XSRF-TOKEN',//default
  xsrfHeaderName:'X-XSRF-TOKEN',//default
  //`onUploadProgress`Upload Progress Event
  onUploadProgress:function(progressEvent){
    //Download Progress Events
onDownloadProgress:function(progressEvent){
}
  },
  //Maximum value of corresponding content
  maxContentLength:2000,
  //`validateStatus` defines whether resolve or reject promise is based on the http corresponding status code
  //If `validateStatus` returns true (or is set to `null` or `undefined`), then the state of promise will be resolved, otherwise it will be rejected
  validateStatus:function(status){
    return status >= 200 && status <300;//default
  },
  //`maxRedirects` defines the maximum number of redirections in nodejs
  maxRedirects: 5,//default
  //`httpAgent/httpsAgent`Defines a custom proxy to use when sending http/https requests
  //keeyAlive is not activated by default in the selection
  httpAgent: new http.Agent({keeyAlive:true}),
  httpsAgent: new https.Agent({keeyAlive:true}),
  //The proxy defines the host name and port number.
  //`auth` indicates that http basic authentication should link to proxy proxy and provide a certificate
  //This will set a `Proxy-Authorization`header and will overwrite the existing `Proxy-Authorization`header
  proxy: {
    host:'127.0.0.1',
    port: 9000,
    auth: {
      username:'skda',
      password:'radsd'
    }
  },
  //`cancelToken` defines a cancel token to cancel a request
  //See cancelation section for details
  cancelToken: new cancelToken(function(cancel){

  })
}

5. Contents Requested for Return

{

  data:{},
  status:200,
  //http status text returned from the server
  statusText:'OK',
  //Response Header Information
  headers: {},
  //`config` is some configuration information when requested
  config: {}
}

• You can do this to get response information

  axios.get('/user/12345')
  then(function(res){
    console.log(res.data);
    console.log(res.status);
    console.log(res.statusText);
    console.log(res.headers);
    console.log(res.config);
  })

6. Default Configuration

• You can set the default configuration to be valid for all requests

1. Global default configuration

axios.defaults.baseURL = 'http://api.exmple.com';
axios.defaults.headers.common['Authorization'] = AUTH_TOKEN;
axios.defaults.headers.post['content-Type'] = 'appliction/x-www-form-urlencoded';

2. Custom instance default settings

//Configure default configuration when creating instances
var instance = axios.create({
    baseURL: 'https://api.example.com'
});

//Modify configuration when instance is created
instance.defaults.headers.common["Authorization"] = AUTH_TOKEN;

3. Priority in configuration

• The config configurations will be merged in priority, in the order of the default configurations in lib/defauts.js, then the default configurations in the instance, and finally the config parameters in the request. The higher the level backward, the later overrides the previous example.

//The default configuration in the libray directory is used when creating an instance
//Here the timeout configuration has a value of 0, which comes from the default value of libray
var instance = axios.create();
//Back override library defaults
//Now all requests will wait 2.5S before they are sent out
instance.defaults.timeout = 2500;
//Here timeout goes back to overwriting the previous 2.5S to 5s
instance.get('/longRequest',{
  timeout: 5000
});

7. Interceptors

• You can intercept requests and responses before they reach then/catch

//Add a request interceptor
axios.interceptors.request.use(function(config){
  //Do something before the request is sent
  return config;
},function(err){
  //Do something with request error
  return Promise.reject(error);
});
//Add a response interceptor
axios.interceptors.response.use(function(res){
  //Processing the returned data here
  return res;
},function(err){
  //Do something with response error
  return Promise.reject(error);
})

2. Cancel Interceptor

var myInterceptor = axios.interceptor.request.use(function(){/*....*/});
axios.interceptors.request.eject(myInterceptor);

3. Add interceptors to custom axios instances

var instance = axios.create();
instance.interceptors.request.use(function(){})

8. Error Handling

axios.get('/user/12345')
  .catch(function(error){
    if(error.response){
      //The request has been sent, but is the status returned by the server response not within the range of 2xx
      console.log(error.response.data);
      console.log(error.response.status);
      console.log(error.response.header);
    }else {
      //Some errors are triggered when the request is set
      console.log('Error',error.message);
    }
    console.log(error.config);
  });

9. Cancellation

• You can cancel a request with a cancel token

• You can create a cancel using the CancelToken.source factory function token

var CancelToken = axios.CancelToken;
var source = CancelToken.source();

axios.get('/user/12345',{
  cancelToken: source.token
}).catch(function(thrown){
  if(axios.isCancel(thrown)){
    console.log('Request canceled',thrown.message);
  }else {
    //handle error
  }
});

//Cancel request (information parameters can be set)
source.cance("operation canceled by user");

1. You can pass an executor function to the cancelToken constructor to create a cancel token:

   var cancelToken = axios.CancelToken;
   var cance;
   axios.get('/user/12345',{
   cancelToken: new CancelToken(function(c){
    //This executor function accepts a cancel function as an argument
    cancel = c;
   })
   })
   //Cancel Request
   cancel();