call-limit/es5/call-limit.js

"use strict";

var defaultMaxRunning = 50;

var limit = module.exports = function (func, maxRunning) {
  var running = 0;
  var queue = [];
  if (!maxRunning) maxRunning = defaultMaxRunning;
  return function limited() {
    var self = this;
    var args = Array.prototype.slice.call(arguments);
    if (running >= maxRunning) {
      queue.push(args);
      return;
    }
    var cb = typeof args[args.length - 1] === 'function' && args.pop();
    ++running;
    args.push(function () {
      var cbargs = arguments;
      --running;
      cb && process.nextTick(function () {
        cb.apply(self, cbargs);
      });
      if (queue.length) {
        var next = queue.shift();
        limited.apply(self, next);
      }
    });
    func.apply(self, args);
  };
};

module.exports.method = function (classOrObj, method, maxRunning) {
  if (typeof classOrObj === 'function') {
    var func = classOrObj.prototype[method];
    classOrObj.prototype[method] = limit(func, maxRunning);
  } else {
    var func = classOrObj[method];
    classOrObj[method] = limit(func, maxRunning);
  }
};