js 根据url生成文件

//根据url生成文件
        getFileFromUrl(fileName, url) {
            return new Promise((resolve, reject) => {
                var blob = null;
                let file
                var xhr = new XMLHttpRequest();
                xhr.open("GET", url, true);
                xhr.setRequestHeader('Accept', 'application/pdf');
                xhr.responseType = "blob";
                // 加载时处理
                xhr.onload = () => {
                    // 获取返回结果
                    blob = xhr.response;
                    file = new File([blob], fileName, { type: 'application/pdf' });
                    // window.open(URL.createObjectURL(file))
                    // 返回结果
                    resolve(file);
                };
                xhr.send();

            })
        },
        //调用
        this.getFileFromUrl(fileName,
                    url)then((response) => {
                        console.log(response)
                    })

 参考：https://blog.csdn.net/waxuanwa/article/details/125624577