HttpRequest.md

//使用promise封装Ajax
window.getRequest = function (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 === 200) {
                    resolve(this.responseText, this)
                } else {
                    var resJson = { code: this.status, response: this.response }
                    reject(resJson, this)
                }
            }
        }
        xhr.send()
    })

}

window.postRequest = function (url, data) {
    console.log('post请求参数',data)
    return new Promise( (resolve, reject) => {
        var xhr = new XMLHttpRequest()
        xhr.open("POST", url, true)
        xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        xhr.onreadystatechange = function () {
            if (this.readyState === 4) {
                if (this.status === 200) {
                    // console.log('request请求成功',this.responseText)
                    resolve(JSON.parse(this.responseText), this)
                } else {
                    var resJson = { code: this.status, response: this.response }
                    reject(resJson, this)
                }
            }
        }
        xhr.send(data)
    })
}

//无论promise对象最后状态如何都会执行
Promise.prototype.finally = function (callback) {
let P = this.constructor;
return this.then(
    value => P.resolve(callback()).then(() => value),
    reason => P.resolve(callback()).then(() => { throw reason })
);
};