docs: correct applyEach callback placement

lib/applyEach.js

@@ -2,13 +2,10 @@ import applyEach from './internal/applyEach.js'
 import map from './map.js'
 
 /**
- * Applies the provided arguments to each function in the array, calling
- * `callback` after all functions have completed. If you only provide the first
- * argument, `fns`, then it will return a function which lets you pass in the
- * arguments as if it were a single function call. If more arguments are
- * provided, `callback` is required while `args` is still optional. The results
- * for each of the applied async functions are passed to the final callback
- * as an array.
+ * Returns a function that applies the provided arguments to each function in
+ * `fns`. Pass a callback to the returned function to receive the results as an
+ * array after all functions have completed. Calling the returned function
+ * without a callback returns a Promise for the results.
  *
  * @name applyEach
  * @static
@@ -19,11 +16,8 @@ import map from './map.js'
  * to all call with the same arguments
  * @param {...*} [args] - any number of separate arguments to pass to the
  * function.
- * @param {Function} [callback] - the final argument should be the callback,
- * called when all functions have completed processing.
  * @returns {AsyncFunction} - Returns a function that takes no args other than
- * an optional callback, that is the result of applying the `args` to each
- * of the functions.
+ * an optional callback. If no callback is passed, it returns a Promise.
  * @example
  *
  * const appliedFn = async.applyEach([enableSearch, updateSchema], 'bucket')
@@ -33,7 +27,12 @@ import map from './map.js'
  *     // results[1] is the results for `updateSchema`
  * });
  *
- * // partial application example:
+ * // or use a Promise:
+ * appliedFn().then(results => {
+ *     console.log(results);
+ * });
+ *
+ * // apply the same functions to each bucket:
  * async.each(
  *     buckets,
  *     async (bucket) => async.applyEach([enableSearch, updateSchema], bucket)(),

lib/applyEachSeries.js

@@ -14,10 +14,8 @@ import mapSeries from './mapSeries.js'
  * call with the same arguments
  * @param {...*} [args] - any number of separate arguments to pass to the
  * function.
- * @param {Function} [callback] - the final argument should be the callback,
- * called when all functions have completed processing.
  * @returns {AsyncFunction} - A function, that when called, is the result of
- * appling the `args` to the list of functions.  It takes no args, other than
- * a callback.
+ * applying the `args` to the list of functions. It takes no args, other than
+ * an optional callback. If no callback is passed, it returns a Promise.
  */
 export default applyEach(mapSeries);