analytics execution time for code block

pfv.js

/**
# Usages:

pfv.start('some');
// some code
// some code
pfv.end();

pfv.check('ff', () => {
  // some code
  // some code
});

pfv.dump(); // get performance of releated code

**/

window.pfv = (() => {
  // {tag: { context, costTime, callTimes, startTime }}
  const performance = typeof tt !== 'undefined' ? tt.getPerformance() : window.performance;
  const map = new Map();
  let contextStack = [];
  const getTag = tag => {
    if (!map.has(tag)) {
      map.set(tag, {
        deep: contextStack.length,
        context: contextStack[0],
        costTime: 0,
        callTimes: 0,
        startTime: performance.now()
      });
    }
    return map.get(tag);
  };
  const endCurrentTag = () => {
    const tag = contextStack.shift();
    const d = map.get(tag);
    d.callTimes++;
    d.costTime += performance.now() - d.startTime;
  };

  return {
    track(tag, f) {
      this.start(tag);
      f();
      this.end();
    },
    start(tag) {
      contextStack.unshift(tag);
      getTag(tag).startTime = performance.now();
    },
    end(tag) {
      if (tag) {
        while(contextStack.length > 0 && contextStack[0] !== tag) {
          endCurrentTag();
        }
        endCurrentTag();
      } else {
        endCurrentTag();
      }
    },
    dump() {
      let str = '';
      [...map.entries()].forEach(([tag, d]) => {
        str += `${'='.repeat(d.deep)}${tag}: ${d.callTimes}, ${d.costTime}\n`;
      });
      console.log(str);
      contextStack = [];
      map.clear();
    },
    data() {
      return map
    }
  }
})();