将BlobURL转成File

/**
 * BlobUrl转blob数据  
 * @param {Object} url blob URL
 * @param {Object} callback 回调函数
 */
function objectURLToBlob(url, callback) {  
    const http = new XMLHttpRequest();  
    http.open("GET", url, true);  
    http.responseType = "blob";  
    http.onload = function (e) {  
        if (this.status == 200 || this.status === 0) {  
            callback(this.response);
        }  
    };  
    http.send();
}; 

// 调用
objectURLToBlob(result.tempFilePath, function (blob) {  
    const file = new window.File([blob], 'avatar.png', {type: blob.type});
    //创建一个FormData对象，然后通过append() 方法向对象中添加键值对
    const formData = new window.FormData(); 
    formData.append(file.name, file);
});