图片转File对象

//文件转base64 
function toDataURL(url) {
    fetch(url)
        .then(response => response.blob())
        .then(blob => new Promise((resolve, reject) => {
            const reader = new FileReader()
            reader.onloadend = () => resolve(reader.result)
            reader.onerror = reject
            reader.readAsDataURL(blob)
        }));
}
//base64转File对象
function base64ToFileObj(filePath, fileName) {
    toDataURL(filePath)
        .then(dataUrl => {
            console.log('RESULT:', dataUrl.length)
            //base64文本
            const url = dataUrl;
            //base64转file对象 
            fetch(url)
                .then(res => res.blob())
                .then(blob => {
                    const file = new File([blob], fileName, {
                        type: "image/png"
                    })
                    //最终输出的文件对象
                    console.log('fileObj', file);
                });
        })
}