TTI Polyfill

// ==UserScript==
// @name         Time to Consistently Interactive Polyfill
// @namespace    http://developers.google.com/
// @version      0.1
// @description  Polyfill to detect Time to Interactive
// @author       Deepanjan Roy
// @include      http://*
// @include      https://*
// @run-at       document-start
// @noframes
// @grant        none
// ==/UserScript==

(function(){var e="undefined"!=typeof window&&window===this?this:"undefined"!=typeof global&&null!=global?global:this,h="function"==typeof Object.defineProperties?Object.defineProperty:function(a,b,c){a!=Array.prototype&&a!=Object.prototype&&(a[b]=c.value)};function k(){k=function(){};e.Symbol||(e.Symbol=m)}var n=0;function m(a){return"jscomp_symbol_"+(a||"")+n++}
function p(){k();var a=e.Symbol.iterator;a||(a=e.Symbol.iterator=e.Symbol("iterator"));"function"!=typeof Array.prototype[a]&&h(Array.prototype,a,{configurable:!0,writable:!0,value:function(){return q(this)}});p=function(){}}function q(a){var b=0;return r(function(){return b<a.length?{done:!1,value:a[b++]}:{done:!0}})}function r(a){p();a={next:a};a[e.Symbol.iterator]=function(){return this};return a}function t(a){p();var b=a[Symbol.iterator];return b?b.call(a):q(a)}
function u(a){if(!(a instanceof Array)){a=t(a);for(var b,c=[];!(b=a.next()).done;)c.push(b.value);a=c}return a}var v=0;function w(a,b){var c=XMLHttpRequest.prototype.send,d=v++;XMLHttpRequest.prototype.send=function(l){for(var f=[],g=0;g<arguments.length;++g)f[g-0]=arguments[g];var F=this;a(d);this.addEventListener("readystatechange",function(){4===F.readyState&&b(d)});return c.apply(this,f)}}
function x(a,b){var c=fetch;fetch=function(d){for(var l=[],f=0;f<arguments.length;++f)l[f-0]=arguments[f];return new Promise(function(d,f){var g=v++;a(g);c.apply(null,[].concat(u(l))).then(function(a){b(g);d(a)},function(a){b(a);f(a)})})}}var y="img script iframe link audio video source".split(" ");function z(a,b){a=t(a);for(var c=a.next();!c.done;c=a.next())if(c=c.value,b.includes(c.nodeName.toLowerCase())||z(c.children,b))return!0;return!1}
function A(a){var b=new MutationObserver(function(c){c=t(c);for(var b=c.next();!b.done;b=c.next())b=b.value,"childList"==b.type&&z(b.addedNodes,y)?a(b):"attributes"==b.type&&y.includes(b.target.tagName.toLowerCase())&&a(b)});b.observe(document,{attributes:!0,childList:!0,subtree:!0,attributeFilter:["href","src"]});return b}function B(a){for(var b=[],c=0;c<arguments.length;++c)b[c-0]=arguments[c];console.log.apply(console,[].concat(u(b)))}
function C(a,b){if(2<a.length)return performance.now();var c=[];b=t(b);for(var d=b.next();!d.done;d=b.next())d=d.value,c.push({timestamp:d.start,type:"requestStart"}),c.push({timestamp:d.end,type:"requestEnd"});b=t(a);for(d=b.next();!d.done;d=b.next())c.push({timestamp:d.value,type:"requestStart"});c.sort(function(a,b){return a.timestamp-b.timestamp});a=a.length;for(b=c.length-1;0<=b;b--)switch(d=c[b],d.type){case "requestStart":a--;break;case "requestEnd":a++;if(2<a)return d.timestamp;break;default:throw Error("Internal Error: This should never happen");
}return 0}
function D(a){a=a?a:{};this.w=!!a.useMutationObserver;this.v=a.minValue||null;a=window.__tti&&window.__tti.e;var b=window.__tti&&window.__tti.o;a?(B("Consuming the long task entries already recorded."),this.a=a.map(function(a){return{start:a.startTime,end:a.startTime+a.duration}})):this.a=[];b&&b.disconnect();this.c=[];this.b=new Map;this.l=null;this.j=-Infinity;this.i=!1;this.h=this.g=this.u=null;w(this.s.bind(this),this.m.bind(this));x(this.s.bind(this),this.m.bind(this));E(this);this.w&&(this.h=
A(this.B.bind(this)))}D.prototype.getFirstConsistentlyInteractive=function(){var a=this;return new Promise(function(b){a.u=b;"complete"==document.readyState?G(a):window.addEventListener("load",function(){G(a)})})};function G(a){B("Enabling FirstConsistentlyInteractiveDetector");a.i=!0;var b=0<a.a.length?a.a[a.a.length-1].end:0,c=C(a.f,a.c);H(a,Math.max(c+5E3,b))}
function H(a,b){a.i?(B("Attempting to reschedule FirstConsistentlyInteractive check to "+b),B("Previous timer activation time: "+a.j),a.j>b?B("Current activation time is greater than attempted reschedule time. No need to postpone."):(clearTimeout(a.l),a.l=setTimeout(function(){B("Checking if First Consistently Interactive was reached...");var b=performance.timing.navigationStart,d=C(a.f,a.c),l=(window.a&&window.a.A?1E3*window.a.A().C-b:0)||performance.timing.domContentLoadedEventEnd-b;if(a.v)var f=
a.v;else performance.timing.domContentLoadedEventEnd?(f=performance.timing,f=f.domContentLoadedEventEnd-f.navigationStart):f=null;var g=performance.now();null===f&&(B("No usable minimum value yet. Postponing check."),H(a,Math.max(d+5E3,g+1E3)));B("Parameter values:");B("NavigationStart",b);B("lastKnownNetwork2Busy",d);B("Search Start",l);B("Min Value",f);B("Last busy",d);B("Current time",g);B("Long tasks",a.a);B("Incomplete JS Request Start Times",a.f);B("Network requests",a.c);b=a.a;5E3>g-d?d=null:
(d=b.length?b[b.length-1].end:l,d=5E3>g-d?null:Math.max(d,f));d&&(a.u(d),B("Disabling FirstConsistentlyInteractiveDetector"),clearTimeout(a.l),a.i=!1,a.g&&a.g.disconnect(),a.h&&a.h.disconnect());B("Could not detect First Consistently Interactive. Retrying in 1 second.");H(a,performance.now()+1E3)},b-performance.now()),a.j=b,B("Rescheduled firstConsistentlyInteractive check at "+b))):B("startSchedulingTimerTasks must be called before calling rescheduleTimer")}
function E(a){a.g=new PerformanceObserver(function(b){b=t(b.getEntries());for(var c=b.next();!c.done;c=b.next())if(c=c.value,"resource"===c.entryType&&(B("Network request finished",c),a.c.push({start:c.fetchStart,end:c.responseEnd}),H(a,C(a.f,a.c)+5E3)),"longtask"===c.entryType){B("Long task finished",c);var d=c.startTime+c.duration;a.a.push({start:c.startTime,end:d});H(a,d+5E3)}});a.g.observe({entryTypes:["longtask","resource"]})}
D.prototype.s=function(a){B("Starting JS initiated request. Request ID: "+a);this.b.set(a,performance.now());B("Active XHRs: "+this.b.size)};D.prototype.m=function(a){B("Completed JS initiated request with request ID: "+a);this.b.delete(a);B("Active XHRs: "+this.b.size)};D.prototype.B=function(a){B("Potentially network resource fetching mutation detected",a);B("Pushing back FirstConsistentlyInteractive check by 5 seconds.");H(this,performance.now()+5E3)};
e.Object.defineProperties(D.prototype,{f:{configurable:!0,enumerable:!0,get:function(){return[].concat(u(this.b.values()))}}});var I={getFirstConsistentlyInteractive:function(a){a=a?a:{};return"PerformanceLongTaskTiming"in window?(new D(a)).getFirstConsistentlyInteractive():Promise.resolve(null)}};"undefined"!=typeof module&&module.exports?module.exports=I:"function"===typeof define&&define.amd?define("ttiPolyfill",[],function(){return I}):window.ttiPolyfill=I;})();

ttiPolyfill.getFirstConsistentlyInteractive().then(console.log);