notesnook/apps/mobile/polyfills/console-time.js

const PerformanceNow =
  (global.performance && global.performance.now) ||
  global.performanceNow ||
  global.nativePerformanceNow ||
  (() => {
    try {
      var now = () => Date.now();
    } finally {
      return now;
    }
  })();

const DEFAULT_LABEL = "default";
const DEFAULT_PREC = 3;

let counts = {};
let startTimes = {};

const fixed = (n) => (Math.trunc(n) === n ? n + "" : n.toFixed(DEFAULT_PREC));

console.time =
  console.time ||
  ((label = DEFAULT_LABEL) => {
    startTimes[label] = PerformanceNow();
  });
console.timeLog =
  console.timeLog || ((label = DEFAULT_LABEL, desc) => timeRecord(label, desc));
console.timeEnd =
  console.timeEnd ||
  ((label = DEFAULT_LABEL) => timeRecord(label, undefined, true));

console.count =
  console.count ||
  ((label = DEFAULT_LABEL) => {
    if (!counts[label]) {
      counts[label] = 0;
    }
    counts[label]++;
    console.log(`${label}: ${counts[label]}`);
  });

console.countReset =
  console.countReset ||
  ((label = DEFAULT_LABEL) => {
    if (counts[label]) {
      counts[label] = 0;
    } else {
      console.warn(`Count for '${label}' does not exist`);
    }
  });

function timeRecord(label, desc, final) {
  const endTime = PerformanceNow();
  const startTime = startTimes[label];
  if (startTime) {
    const delta = endTime - startTime;
    if (desc) {
      console.log(`${label}: ${fixed(delta)}ms ${desc}`);
    } else {
      console.log(`${label}: ${fixed(delta)}ms`);
    }
    if (final) delete startTimes[label];
  } else {
    console.warn(`Timer '${label}' does not exist`);
  }
}