Cross-browser Base64 object

cbBase64.ts

/**
 * @see https://stackoverflow.com/a/26514148/6087422
 * @description Cross-browser Base64 object (compatible with TypeScript). Based on the attached StackOverflow answer by <a href="https://stackoverflow.com/users/1922144/davidcondrey" target="_blank">davidcondrey</a>
 * Use case: This script is an alternative to the <a href="https://nodejs.org/docs/latest-v18.x/api/crypto.html" target="_blank">crypto</a> <b>Node.js module</b> in <a href="https://nextjs.org/docs/messages/node-module-in-edge-runtime" target="_blank">Next.js Edge functions (e.g.: middleware)</a>
 */


const Base64 = {
  _keyStr:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
  encode:function(e: any){
    let t="";
    let n,r,i,s,o,u,a;
    let f=0;
    e=Base64._utf8_encode(e);
    while(f<e.length){
      n=e.charCodeAt(f++);
      r=e.charCodeAt(f++);
      i=e.charCodeAt(f++);
      s=n>>2;
      o=(n&3)<<4|r>>4;
      u=(r&15)<<2|i>>6;
      a=i&63;

      if(isNaN(r)){u=a=64}
      else if(isNaN(i)){a=64}

      t=t+this._keyStr.charAt(s)+this._keyStr.charAt(o)+this._keyStr.charAt(u)+this._keyStr.charAt(a)
    }
    return t
  },
  decode:function(e: any){
    let t="";
    let n,r,i;
    let s,o,u,a;
    let f=0;
    e=e.replace(/[^A-Za-z0-9\+\/\=]/g,"");
    while(f<e.length){
      s=this._keyStr.indexOf(e.charAt(f++));
      o=this._keyStr.indexOf(e.charAt(f++));
      u=this._keyStr.indexOf(e.charAt(f++));
      a=this._keyStr.indexOf(e.charAt(f++));
      n=s<<2|o>>4;
      r=(o&15)<<4|u>>2;
      i=(u&3)<<6|a;
      t=t+String.fromCharCode(n);

      if(u!=64){t=t+String.fromCharCode(r)}
      if(a!=64){t=t+String.fromCharCode(i)}
    }
    t=Base64._utf8_decode(t);
    return t
  },
  _utf8_encode:function(e: any){
    e=e.replace(/\r\n/g,"\n");
    let t="";
    for(let n=0;n<e.length;n++){
      let r=e.charCodeAt(n);
      if(r<128){
        t+=String.fromCharCode(r)
      }
      else if(r>127&&r<2048){
        t+=String.fromCharCode(r>>6|192);
        t+=String.fromCharCode(r&63|128)
      }
      else{t+=String.fromCharCode(r>>12|224);
        t+=String.fromCharCode(r>>6&63|128);
        t+=String.fromCharCode(r&63|128)}
    }
    return t
  },
  _utf8_decode:function(e: any){
    let t="";
    let n=0;
    let c1, c2, c3 = 0;
    let r=c1=c2=0;
    while(n<e.length){
      r=e.charCodeAt(n);
      if(r<128){
        t+=String.fromCharCode(r);
        n++
      }else if(r>191&&r<224){
        c2=e.charCodeAt(n+1);
        t+=String.fromCharCode((r&31)<<6|c2&63);
        n+=2
      }else{
        c2=e.charCodeAt(n+1);
        c3=e.charCodeAt(n+2);
        t+=String.fromCharCode((r&15)<<12|(c2&63)<<6|c3&63);
        n+=3
      }
    }
    return t
  }
}
export default Base64;