base64 web front end js decoding and transcoding

Reprinted: https://blog.csdn.net/xieamy/article/details/78846732

Encoding, it is converted into a string base64 

    function b64EncodeUnicode(str) {
    return btoa(encodeURIComponent(str).replace(/%([0-9A-F]{2})/g, function(match, p1) {
        return String.fromCharCode('0x' + p1);
    }));

Decoding: base64 is converted into a string

function b64DecodeUnicode(str) {
    return decodeURIComponent(atob(str).split('').map(function(c) {
        return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2);
    }).join(''));
}