A Node.js file system walker extracted from fs-extra.
npm i --save klaw
If you're using Typescript, we've got types:
npm i --save-dev @types/klaw
klaw is walk backwards :p
If you need the same functionality but synchronous, you can use klaw-sync.
Returns a Readable stream 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.
directory: The directory to recursively walk. Typestring.options: Readable stream options and the following:queueMethod(string, default:'shift'): Either'shift'or'pop'. Onreaddir()array, call eithershift()orpop().pathSorter(function, default:undefined): Sorting function for Arrays.fs(object, default:require('fs')): Use this to hook into thefsmethods or to usemock-fsfilter(function, default:undefined): Filtering function for Arrays
Streams 1 (push) example:
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:
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/.
Listen for the error event.
Example:
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]
})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 to easily
accomplish this.
Install through2:
npm i --save through2
Example (skipping directories):
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):
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):
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):
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.unlink(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):
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:
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]
})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 :)
MIT
Copyright (c) 2015 JP Richardson
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