data uri for manifest about pwacompat HOT 5 CLOSED

 function setup() {
    const manifestEl = document.head.querySelector('link[rel="manifest"]');
    const manifestHref = manifestEl ? manifestEl.href : '';
    if (!manifestHref) {
      throw `can't find <link rel="manifest" href=".." />'`;
    }

    const hrefFactory = buildHrefFactory([manifestHref, window.location]);
    const datauri=decodeBase64(manifestHref.split(',')[1]);
    if(datauri){
     try {
       const data = (JSON.parse(datauri));
       process(data, hrefFactory);
     } catch (err) {
       console.warn('pwacompat.js error', err)
     }
    } else {
     const xhr = new XMLHttpRequest();
     xhr.open('GET', manifestHref);

     // nb. use getAttribute for older brower safety
     xhr.withCredentials = (manifestEl.getAttribute('crossorigin') === 'use-credentials');

     // this is IE10+
     xhr.onload = () => {
       try {
         const data = /** @type {!Object<string, *>} */ (JSON.parse(xhr.responseText));
         process(data, hrefFactory);
       } catch (err) {
         console.warn('pwacompat.js error', err)
       }
     };
     xhr.send(null);
    }
  }

    decodeBase64=function(f){var g={},b=65,d=0,a,c=0,h,e="",k=String.fromCharCode,l=f.length;for(a="";91>b;)a+=k(b++);a+=a.toLowerCase()+"0123456789+/";for(b=0;64>b;b++)g[a.charAt(b)]=b;for(a=0;a<l;a++)for(b=g[f.charAt(a)],d=(d<<6)+b,c+=6;8<=c;)((h=d>>>(c-=8)&255)||a<l-2)&&(e+=k(h));return e};

const hrefFactory = buildHrefFactory([manifestHref, window.location]);