parcel-bundler/lib/Profiler.js

'use strict';

function _asyncToGenerator(fn) { return function () { var gen = fn.apply(this, arguments); return new Promise(function (resolve, reject) { function step(key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { return Promise.resolve(value).then(function (value) { step("next", value); }, function (err) { step("throw", err); }); } } return step("next"); }); }; }

// node.js builtin library
const inspector = require('inspector');

class Profiler {
  constructor() {
    this.session = undefined;
  }

  hasSession() {
    return this.session != null;
  }

  startProfiling() {
    var _this = this;

    return _asyncToGenerator(function* () {
      _this.session = new inspector.Session();
      _this.session.connect();

      return Promise.all([_this.sendCommand('Profiler.setSamplingInterval', {
        interval: 100
      }), _this.sendCommand('Profiler.enable'), _this.sendCommand('Profiler.start')]);
    })();
  }

  sendCommand(method, params) {
    var _this2 = this;

    return _asyncToGenerator(function* () {
      if (_this2.hasSession()) {
        return new Promise(function (resolve, reject) {
          _this2.session.post(method, params, function (err, params) {
            if (err == null) {
              resolve(params);
            } else {
              reject(err);
            }
          });
        });
      }
    })();
  }

  destroy() {
    if (this.hasSession()) {
      this.session.disconnect();
    }
  }

  stopProfiling() {
    var _this3 = this;

    return _asyncToGenerator(function* () {
      const res = yield _this3.sendCommand('Profiler.stop');
      _this3.destroy();
      return res.profile;
    })();
  }
}

module.exports = Profiler;