微信小程序字符串base64轉碼和解碼

class Base64 {

constructor() {

this._keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

}

encode(input) {

var output = "";

var chr1, chr2, chr3, enc1, enc2, enc3, enc4;

var i = 0;

input = this._utf8_encode(input);

while (i < input.length) {

 

chr1 = input.charCodeAt(i++);

 

chr2 = input.charCodeAt(i++);

 

chr3 = input.charCodeAt(i++);

 

enc1 = chr1 >> 2;

 

enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);

 

enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);

 

enc4 = chr3 & 63;

 

if (isNaN(chr2)) {

 

enc3 = enc4 = 64;

 

} else if (isNaN(chr3)) {

 

enc4 = 64;

 

}

 

output = output +

 

this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +

 

this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);

 

}

 

return output;

 

}

decode(input) {

 

var output = "";

 

var chr1, chr2, chr3;

 

var enc1, enc2, enc3, enc4;

 

var i = 0;

 

input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

 

while (i < input.length) {

 

enc1 = this._keyStr.indexOf(input.charAt(i++));

 

enc2 = this._keyStr.indexOf(input.charAt(i++));

 

enc3 = this._keyStr.indexOf(input.charAt(i++));

 

enc4 = this._keyStr.indexOf(input.charAt(i++));

 

chr1 = (enc1 << 2) | (enc2 >> 4);

 

chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);

 

chr3 = ((enc3 & 3) << 6) | enc4;

 

output = output + String.fromCharCode(chr1);

 

if (enc3 != 64) {

 

output = output + String.fromCharCode(chr2);

 

}

 

if (enc4 != 64) {

 

output = output + String.fromCharCode(chr3);

 

}

 

}

 

output = this._utf8_decode(output);

 

return output;

 

}

_utf8_encode(string) {

 

string = string.replace(/\r\n/g, "\n");

 

var utftext = "";

 

for (var n = 0; n < string.length; n++) {

 

var c = string.charCodeAt(n);

 

if (c < 128) {

 

utftext += String.fromCharCode(c);

 

} else if ((c > 127) && (c < 2048)) {

 

utftext += String.fromCharCode((c >> 6) | 192);

 

utftext += String.fromCharCode((c & 63) | 128);

 

} else {

 

utftext += String.fromCharCode((c >> 12) | 224);

 

utftext += String.fromCharCode(((c >> 6) & 63) | 128);

 

utftext += String.fromCharCode((c & 63) | 128);

 

}

}

return utftext;

 

}

_utf8_decode(utftext) {

 

var string = "";

 

let i = 0;

 

let c = 0;

 

let c1 = 0;

 

let c2 = 0;

let c3 = 0;

while (i < utftext.length) {

 

c = utftext.charCodeAt(i);

 

if (c < 128) {

 

string += String.fromCharCode(c);

 

i++;

 

} else if ((c > 191) && (c < 224)) {

 

c2 = utftext.charCodeAt(i + 1);

 

string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));

 

i += 2;

 

} else {

 

c2 = utftext.charCodeAt(i + 1);

c3 = utftext.charCodeAt(i + 2);

 

string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));

 

i += 3;

 

}

 

}

 

return string;

 

}

}

修改他人的代碼，只爲方便使用   原創連接找不到了^*^

使用方式  

var base = new Base64();//保證引入路徑真確

//1.加密   var str = '124中文內容';   var result = base.encode(str);   //document.write(result);      //2.解密   var result2 = base.decode(result);   document.write(result2);