dnssd/lib/Mutex.js

Bonjour/Avahi-like service discovery in pure JavaScript

"use strict";

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

/**
 * const mutex = new Mutex();
 *
 * function limitMe() {
 *   mutex.lock((unlock) => {
 *     asyncFn().then(unlock);
 *   });
 * }
 *
 * limitMe();
 * limitMe(); // <-- will wait for first call to finish & unlock
 *
 */
var Mutex = function () {
  function Mutex() {
    _classCallCheck(this, Mutex);

    this._queue = [];
    this.locked = false;
  }

  _createClass(Mutex, [{
    key: "lock",
    value: function lock(fn) {
      var _this = this;

      var unlock = function unlock() {
        var nextFn = _this._queue.shift();

        if (nextFn) nextFn(unlock);else _this.locked = false;
      };

      if (!this.locked) {
        this.locked = true;
        fn(unlock);
      } else {
        this._queue.push(fn);
      }
    }
  }]);

  return Mutex;
}();

module.exports = Mutex;