Async.js

map.js

  1. import doParallel from './internal/doParallel';
  2. import map from './internal/map';
  4. /**
  5.  * Produces a new collection of values by mapping each value in `coll` through
  6.  * the `iteratee` function. The `iteratee` is called with an item from `coll`
  7.  * and a callback for when it has finished processing. Each of these callback
  8.  * takes 2 arguments: an `error`, and the transformed item from `coll`. If
  9.  * `iteratee` passes an error to its callback, the main `callback` (for the
  10.  * `map` function) is immediately called with the error.
  11.  *
  12.  * Note, that since this function applies the `iteratee` to each item in
  13.  * parallel, there is no guarantee that the `iteratee` functions will complete
  14.  * in order. However, the results array will be in the same order as the
  15.  * original `coll`.
  16.  *
  17.  * If `map` is passed an Object, the results will be an Array.  The results
  18.  * will roughly be in the order of the original Objects' keys (but this can
  19.  * vary across JavaScript engines).
  20.  *
  21.  * @name map
  22.  * @static
  23.  * @memberOf module:Collections
  24.  * @method
  25.  * @category Collection
  26.  * @param {Array|Iterable|Object} coll - A collection to iterate over.
  27.  * @param {AsyncFunction} iteratee - An async function to apply to each item in
  28.  * `coll`.
  29.  * The iteratee should complete with the transformed item.
  30.  * Invoked with (item, callback).
  31.  * @param {Function} [callback] - A callback which is called when all `iteratee`
  32.  * functions have finished, or an error occurs. Results is an Array of the
  33.  * transformed items from the `coll`. Invoked with (err, results).
  34.  * @example
  35.  *
  36.  * async.map(['file1','file2','file3'], fs.stat, function(err, results) {
  37.  *     // results is now an array of stats for each file
  38.  * });
  39.  */
  40. export default doParallel(map);