First, encapsulate the native xhr as an ajax class

xhr and usage see previous articles

1. Determine the request header and other information according to the url.

    var _headerConfig = {};
    if(url.indexOf('getcaptcha') !== -1) {
        _headerConfig = {
            Accept: 'image/png',
            responseType: 'arraybuffer',
        }
    } else if(url.indexOf('files/upload') !== -1) {
        _headerConfig = {
            'Content-Type': 'multipart/form-data',
            responseType: 'json',
        }
    } else {
        _headerConfig = {
            'Content-Type': 'application/json',
            Accept: 'application/json',
            responseType: 'json',
        }
    }

2. Determine the request method and parameters according to the information in the parameter information

    if("method" in options) {
        options.method = options.method.toUpperCase();
    } else {
        options.method = "GET";
    }
    if(options.method !== "GET") {
        if(!(options.params instanceof FormData)) {
            options.params = JSON.stringify(options.params);
        }
    }

3. Open xhr and send according to the head and other information settings

    this.xhr.open(options.method, url, true);
    for(var _i in _headerConfig) {

        if(_i === 'responseType') {
            this.xhr.responseType = _headerConfig[_i];
        } else {
            this.xhr.setRequestHeader(_i, _headerConfig[_i]);
        }
    }
    if(token) {
        this.xhr.setRequestHeader("token", token);
    }
    this.xhr.send(options.params);

4. Implement chain programming: return this at the end of each function;

5. Execute callback after implementation

This problem has been combined with chain programming for a long time.

ajax.prototype.complete = function(completeFunction) {
    this.xhr.onreadystatechange = function(e) {
        if(this.readyState === 4) {
            completeFunction(this);
        }
    }
    return this;
}

2. request class of encapsulation practicability

In a project, it is often necessary to encapsulate the request and use the ajax class to initiate the request. The address function of the splice request.

1. Create a splicing method.

var requstUrl = {
    baseURL: URL,
    API: {
        NEWS: '/news',
        LOGIN: '/',
    },
    // API is a parameter in API, used to splice url
    // method is the address after the API, which is used to splice the last part of the url.
    // params parameters required for get request
    createUrl: function(api, method, params) {
        var _requestUrl = this.baseURL + this.API[api] + method;
        if(params) {
            for(var i of params) {
                _requestUrl += (_requestUrl.indexOf("?") == -1 ? "?" : "&");
                _requestUrl += name + "=" + value;
            }
        }
        return _requestUrl;
    }
}

2. Determine each request.

function handleRequest() {

}

//  get request has parameters.
handleRequest.prototype.getDataUseGet = function(api, method, params) {
    var _url;
    var ajax = new Ajax();
    var token = sessionStorage.getItem('token');
    if(params) {
        _url = requstUrl.createUrl(api, method, params);
    } else {
        _url = requstUrl.createUrl(api, method);
    }
    return ajax.request(_url, {
        method: 'GET',
        params: params
    }, token);
}

//  get request without token
handleRequest.prototype.getDataUseGetWithoutToken = function(api, method, params) {
    var _url;
    var ajax = new Ajax();
    if(params) {
        _url = requstUrl.createUrl(api, method, params);
    } else {
        _url = requstUrl.createUrl(api, method);
    }
    return ajax.request(_url, {
        method: 'GET',
        params: params
    });
}

//  post request with token
handleRequest.prototype.getDataUsePost = function(api, method, params) {
    var _url = requstUrl.createUrl(api, method);
    var token = sessionStorage.getItem('token');
    var ajax = new Ajax();
    console.log(createAjaxObj(_url, {
        method: 'POST',
        params: params
    }, token));
    return ajax.request(_url, {
        method: 'POST',
        params: params
    }, token);
}

//  post request without token
handleRequest.prototype.getDataUsePostWithOutToken = function(api, method, params) {
    var _url = requstUrl.createUrl(api, method);
    var ajax = new Ajax();
    return ajax.request(_url, {
        method: 'POST',
        params: params
    });
}

//  put request with token
handleRequest.prototype.getDataUsePut = function(api, method, params) {
    var _url = requstUrl.createUrl(api, method);
    var token = sessionStorage.getItem('token');
    var ajax = new Ajax();
    return ajax.request(_url, {
        method: 'PUT',
        params: params
    }, token);
}

//  put request without token
handleRequest.prototype.getDataUsePutWithOutToken = function(api, method, params) {
    var _url = requstUrl.createUrl(api, method);
    var ajax = new Ajax();
    return ajax.request(_url, {
        method: 'PUT',
        params: params
    });
}

//  delete request with token
handleRequest.prototype.deleteData = function(api, method, params) {
    var _url = requstUrl.createUrl(api, method);
    var token = sessionStorage.getItem('token');
    var ajax = new Ajax();
    return ajax.request(_url, {
        method: 'DELETE',
        params: params
    }, token);
}

This method feels like it can be encapsulated again.

Three, use

1. Use code

<!DOCTYPE html>
<html>

    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>

    <body>
    </body>
    <script src="ip.js" type="text/javascript"></script>
    <script src="xhr.js" type="text/javascript"></script>
    <script src="request.js" type="text/javascript"></script>
    <script type="text/javascript">

        var data = {
            "captcha": "string",
            "password": "string",
            "username": "string"
        };

        var test = new handleRequest();
        test.getDataUsePostWithOutToken('LOGIN', 'login',data).complete(function(result) {
            console.log(result)
        })
    </script>

</html>

2, result

Request initiated successfully.

Complete code Click to view

Above.