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import eachOf from './eachOf';
import withoutIndex from './internal/withoutIndex';
import wrapAsync from './internal/wrapAsync'
import awaitify from './internal/awaitify'
/**
* Applies the function `iteratee` to each item in `coll`, in parallel.
* The `iteratee` is called with an item from the list, and a callback for when
* it has finished. If the `iteratee` passes an error to its `callback`, the
* main `callback` (for the `each` function) is immediately called with the
* error.
*
* Note, that since this function applies `iteratee` to each item in parallel,
* there is no guarantee that the iteratee functions will complete in order.
*
* @name each
* @static
* @memberOf module:Collections
* @method
* @alias forEach
* @category Collection
* @param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
* @param {AsyncFunction} iteratee - An async function to apply to
* each item in `coll`. Invoked with (item, callback).
* The array index is not passed to the iteratee.
* If you need the index, use `eachOf`.
* @param {Function} [callback] - A callback which is called when all
* `iteratee` functions have finished, or an error occurs. Invoked with (err).
* @returns {Promise} a promise, if a callback is omitted
* @example
*
* // dir1 is a directory that contains file1.txt, file2.txt
* // dir2 is a directory that contains file3.txt, file4.txt
* // dir3 is a directory that contains file5.txt
* // dir4 does not exist
*
* const fileList = [ 'dir1/file2.txt', 'dir2/file3.txt', 'dir/file5.txt'];
* const withMissingFileList = ['dir1/file1.txt', 'dir4/file2.txt'];
*
* // asynchronous function that deletes a file
* const deleteFile = function(file, callback) {
* fs.unlink(file, callback);
* };
*
* // Using callbacks
* async.each(fileList, deleteFile, function(err) {
* if( err ) {
* console.log(err);
* } else {
* console.log('All files have been deleted successfully');
* }
* });
*
* // Error Handling
* async.each(withMissingFileList, deleteFile, function(err){
* console.log(err);
* // [ Error: ENOENT: no such file or directory ]
* // since dir4/file2.txt does not exist
* // dir1/file1.txt could have been deleted
* });
*
* // Using Promises
* async.each(fileList, deleteFile)
* .then( () => {
* console.log('All files have been deleted successfully');
* }).catch( err => {
* console.log(err);
* });
*
* // Error Handling
* async.each(fileList, deleteFile)
* .then( () => {
* console.log('All files have been deleted successfully');
* }).catch( err => {
* console.log(err);
* // [ Error: ENOENT: no such file or directory ]
* // since dir4/file2.txt does not exist
* // dir1/file1.txt could have been deleted
* });
*
* // Using async/await
* async () => {
* try {
* await async.each(files, deleteFile);
* }
* catch (err) {
* console.log(err);
* }
* }
*
* // Error Handling
* async () => {
* try {
* await async.each(withMissingFileList, deleteFile);
* }
* catch (err) {
* console.log(err);
* // [ Error: ENOENT: no such file or directory ]
* // since dir4/file2.txt does not exist
* // dir1/file1.txt could have been deleted
* }
* }
*
*/
function eachLimit(coll, iteratee, callback) {
return eachOf(coll, withoutIndex(wrapAsync(iteratee)), callback);
}
export default awaitify(eachLimit, 3)
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