base64js typescript代码改写

桃扇骨 2022-10-02 06:48 249阅读 0赞

[2019独角兽企业重金招聘Python工程师标准>>> ][2019_Python_] ![hot3.png][]

将市面上的base64方法改写为typescript类  需要的拿走不谢

export class Base64 {
    
      // private property
      private _keyStr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
    
      // public method for encoding
      encode(input) {
        let output = '';
        let chr1, chr2, chr3, enc1, enc2, enc3, enc4;
        let 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;
      }
    
      // public method for decoding
      decode(input) {
        let output = '';
        let chr1, chr2, chr3;
        let enc1, enc2, enc3, enc4;
        let 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;
      }
    
      // private method for UTF-8 encoding
      private _utf8_encode(string) {
        string = string.replace(/\r\n/g, '\n');
        let utftext = '';
        for (let n = 0; n < string.length; n++) {
          const 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;
      }
    
      // private method for UTF-8 decoding
      private _utf8_decode(utftext) {
        let string = '';
        let i = 0;
        let c = 0, c2 = 0, 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;
      }
    }

转载于:https://my.oschina.net/lilugirl2005/blog/3058514

[2019_Python_]: https://my.oschina.net/u/2663968/blog/3061697
[hot3.png]: /images/20220113/35629f0512664d6da4cf81a4accb2c23.png