Node.js - klaw ============== A Node.js file system walker extracted from [fs-extra](https://github.com/jprichardson/node-fs-extra). [![npm Package](https://img.shields.io/npm/v/klaw.svg?style=flat-square)](https://www.npmjs.org/package/klaw) [![build status](https://api.travis-ci.org/jprichardson/node-klaw.svg)](http://travis-ci.org/jprichardson/node-klaw) [![windows build status](https://ci.appveyor.com/api/projects/status/github/jprichardson/node-klaw?branch=master&svg=true)](https://ci.appveyor.com/project/jprichardson/node-klaw/branch/master) Standard Install ------- npm i --save klaw Name ---- `klaw` is `walk` backwards :p Usage ----- ### klaw(directory, [options]) Returns a [Readable stream](https://nodejs.org/api/stream.html#stream_class_stream_readable) that iterates through every file and directory starting with `dir` as the root. Every `read()` or `data` event returns an object with two properties: `path` and `stats`. `path` is the full path of the file and `stats` is an instance of [fs.Stats](https://nodejs.org/api/fs.html#fs_class_fs_stats). - `directory`: The directory to recursively walk. Type `string`. - `options`: [Readable stream options](https://nodejs.org/api/stream.html#stream_new_stream_readable_options) and the following: - `queueMethod` (`string`, default: `'shift'`): Either `'shift'` or `'pop'`. On `readdir()` array, call either `shift()` or `pop()`. - `pathSorter` (`function`, default: `undefined`): Sorting [function for Arrays](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort). - `fs` (`object`, default: `require('fs')`): Use this to hook into the `fs` methods or to use [`mock-fs`](https://github.com/tschaub/mock-fs) - `filter` (`function`, default: `undefined`): Filtering [function for Arrays](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter) **Streams 1 (push) example:** ```js var klaw = require('klaw') var items = [] // files, directories, symlinks, etc klaw('/some/dir') .on('data', function (item) { items.push(item.path) }) .on('end', function () { console.dir(items) // => [ ... array of files] }) ``` **Streams 2 & 3 (pull) example:** ```js var klaw = require('klaw') var items = [] // files, directories, symlinks, etc klaw('/some/dir') .on('readable', function () { var item while ((item = this.read())) { items.push(item.path) } }) .on('end', function () { console.dir(items) // => [ ... array of files] }) ``` If you're not sure of the differences on Node.js streams 1, 2, 3 then I'd recommend this resource as a good starting point: https://strongloop.com/strongblog/whats-new-io-js-beta-streams3/. ### Error Handling Listen for the `error` event. Example: ```js var klaw = require('klaw') klaw('/some/dir') .on('readable', function () { var item while ((item = this.read())) { // do something with the file } }) .on('error', function (err, item) { console.log(err.message) console.log(item.path) // the file the error occurred on }) .on('end', function () { console.dir(items) // => [ ... array of files] }) ``` ### Aggregation / Filtering / Executing Actions (Through Streams) On many occasions you may want to filter files based upon size, extension, etc. Or you may want to aggregate stats on certain file types. Or maybe you want to perform an action on certain file types. You should use the module [`through2`](https://www.npmjs.com/package/through2) to easily accomplish this. Install `through2`: npm i --save through2 **Example (skipping directories):** ```js var klaw = require('klaw') var through2 = require('through2') var excludeDirFilter = through2.obj(function (item, enc, next) { if (!item.stats.isDirectory()) this.push(item) next() }) var items = [] // files, directories, symlinks, etc klaw('/some/dir') .pipe(excludeDirFilter) .on('data', function (item) { items.push(item.path) }) .on('end', function () { console.dir(items) // => [ ... array of files without directories] }) ``` **Example (ignore hidden directories):** ```js var klaw = require('klaw') var path = require('path') var filterFunc = function(item){ var basename = path.basename(item) return basename === '.' || basename[0] !== '.' } klaw('/some/dir', { filter : filterFunc }) .on('data', function(item){ // only items of none hidden folders will reach here }) ``` **Example (totaling size of PNG files):** ```js var klaw = require('klaw') var path = require('path') var through2 = require('through2') var totalPngsInBytes = 0 var aggregatePngSize = through2.obj(function (item, enc, next) { if (path.extname(item.path) === '.png') { totalPngsInBytes += item.stats.size } this.push(item) next() }) klaw('/some/dir') .pipe(aggregatePngSize) .on('data', function (item) { items.push(item.path) }) .on('end', function () { console.dir(totalPngsInBytes) // => total of all pngs (bytes) }) ``` **Example (deleting all .tmp files):** ```js var fs = require('fs') var klaw = require('klaw') var through2 = require('through2') var deleteAction = through2.obj(function (item, enc, next) { this.push(item) if (path.extname(item.path) === '.tmp') { item.deleted = true fs.unklink(item.path, next) } else { item.deleted = false next() } }) var deletedFiles = [] klaw('/some/dir') .pipe(deleteAction) .on('data', function (item) { if (!item.deleted) return deletedFiles.push(item.path) }) .on('end', function () { console.dir(deletedFiles) // => all deleted files }) ``` You can even chain a bunch of these filters and aggregators together. By using multiple pipes. **Example (using multiple filters / aggregators):** ```js klaw('/some/dir') .pipe(filterCertainFiles) .pipe(deleteSomeOtherFiles) .on('end', function () { console.log('all done!') }) ``` **Example passing (piping) through errors:** Node.js does not `pipe()` errors. This means that the error on one stream, like `klaw` will not pipe through to the next. If you want to do this, do the following: ```js var klaw = require('klaw') var through2 = require('through2') var excludeDirFilter = through2.obj(function (item, enc, next) { if (!item.stats.isDirectory()) this.push(item) next() }) var items = [] // files, directories, symlinks, etc klaw('/some/dir') .on('error', function (err) { excludeDirFilter.emit('error', err) }) // forward the error on .pipe(excludeDirFilter) .on('data', function (item) { items.push(item.path) }) .on('end', function () { console.dir(items) // => [ ... array of files without directories] }) ``` ### Searching Strategy Pass in options for `queueMethod` and `pathSorter` to affect how the file system is recursively iterated. See the code for more details, it's less than 50 lines :) License ------- MIT Copyright (c) 2015 [JP Richardson](https://github.com/jprichardson)