react-router/lib/AsyncUtils.js

A complete routing library for React.js

"use strict";

exports.__esModule = true;
exports.loopAsync = loopAsync;
exports.mapAsync = mapAsync;

function loopAsync(turns, work, callback) {
  var currentTurn = 0,
      isDone = false;

  function done() {
    isDone = true;
    callback.apply(this, arguments);
  }

  function next() {
    if (isDone) return;

    if (currentTurn < turns) {
      work.call(this, currentTurn++, next, done);
    } else {
      done.apply(this, arguments);
    }
  }

  next();
}

function mapAsync(array, work, callback) {
  var length = array.length;
  var values = [];

  if (length === 0) return callback(null, values);

  var isDone = false,
      doneCount = 0;

  function done(index, error, value) {
    if (isDone) return;

    if (error) {
      isDone = true;
      callback(error);
    } else {
      values[index] = value;

      isDone = ++doneCount === length;

      if (isDone) callback(null, values);
    }
  }

  array.forEach(function (item, index) {
    work(item, index, function (error, value) {
      done(index, error, value);
    });
  });
}