js blobToBase64

blob 转 base64

const reader = new FileReader();
reader.onload = function() {
    const base64 = reader.result.split(',')[1];
    console.log(base64);
};
reader.readAsDataURL(blob);

base64 转 blob

function base64ToBlob(base64) {
    const arr = base64.split(',');
    const mime = arr[0].match(/:(.*?);/)[1];
    const bstr = atob(arr[1]);
    let n = bstr.length;
    const u8arr = new Uint8Array(n);
    while (n--) {
        u8arr[n] = bstr.charCodeAt(n);
    }
    return new Blob([u8arr], { type: mime });
}