Using the Promise encapsulation simple Ajax method __ajax

Always enjoy using native JavaScript, especially if you don't need to consider compatibility scenarios (albeit pitifully). Unfortunately ECMAScript does not encapsulate a good Ajax method (in fact, there is no need to have), the use of their own promise a bar. Get

function Getjson (URL) {return
    new Promise (Resolve, Reject) => {
        var xhr = new XMLHttpRequest ()
        Xhr.open (' Get ', url, true)

        Xhr.onreadystatechange = function () {
            if (this.readystate = = 4) {
                if (this.status = =) {
                    Resolve (this.re Sponsetext, this)
                } else {
                    var Resjson = {code:this.status, response:this.response}
                    reject (Resjson, this }}}

        xhr.send ()}
    )

}

POST

function Postjson (URL, data) {return
    new Promise (Resolve, Reject) => {
        var xhr = new XMLHttpRequest ()
        XH R.open ("POST", url, True)
        Xhr.setrequestheader ("Content-type", "application/x-www-form-urlencoded");

        Xhr.onreadystatechange = function () {
            if (this.readystate = = 4) {
                if (this.status = =) {
                    Resolve (JSON.PA RSE (This.responsetext), this)
                } else {
                    var Resjson = {code:this.status, response:this.response}
                    reject (r Esjson, this)}}

        xhr.send (json.stringify (data)
    })
}

In fact, promise is a natural try...catch

Getjson ('/api/v1/xxx ')    //=> This is just a try
. catch (Error => {/
  /dosomething          //=> Here is the catch to the error, if handling the error and returning the appropriate value
})
. Then (value => {
  //dosomething//          here is final
})