Base64 Coder

base64coder.js

const Base64 = {
  keys: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',
  encode(string){
    let output = '';
    for (let i = 0, max = string.length; i < max; i++) {
      const code1 = string.charCodeAt(i);
      i++;
      const code2 = string.charCodeAt(i);
      i++;
      const code3 = string.charCodeAt(i);
      let base1 = code1 >> 2;
      let base2 = ((code1 & 3) << 4) | (code2 >> 4);
      let base3 = ((code2 & 15) << 2) | (code3 >> 6);
      let base4 = code3 & 63;
      if (isNaN(code2)) {
        base3 = 64;
        base4 = 64;
      } else if (isNaN(code3)) { base4 = 64; }
      output += this.keys[base1] + this.keys[base2] + this.keys[base3] + this.keys[base4];
    }
    return output;
  },
  decode(string) {
    let output = '';
    for (let i = 0, max = string.length; i < max; i++) {
      const base1 = this.keys.indexOf(string[i]);
      i++;
      const base2 = this.keys.indexOf(string[i]);
      i++;
      const base3 = this.keys.indexOf(string[i]);
      i++;
      const base4 = this.keys.indexOf(string[i]);
      const code1 = (base1 << 2) | (base2 >> 4);
      const code2 = ((base2 & 15) << 4) | (base3 >> 2);
      const code3 = ((base3 & 3) << 6) | base4;

      output += String.fromCharCode(code1) + String.fromCharCode(code2) + String.fromCharCode(code3);
    }
    return output;
  },
};
/*
* USAGE
* Base64.encode('string');
* Base64.decode('HN0cmluZyEh');
*/

Base64Coder.markdown

Base64 Coder

Encodes/decodes strings to/from Base64.

A script by V.

License.