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5.0.0 • Public • Published


Node JS directory compare

Starting with v3.0.0 the CLI utility moved to dir-compare-cli.

Build status codecov.io


npm install dir-compare



const dircompare = require('dir-compare');

const options = { compareSize: true };
// Multiple compare strategy can be used simultaneously - compareSize, compareContent, compareDate, compareSymlink.
// If one comparison fails for a pair of files, they are considered distinct.
const path1 = '...';
const path2 = '...';

// Synchronous
const res = dircompare.compareSync(path1, path2, options)

// Asynchronous
dircompare.compare(path1, path2, options)
  .then(res => print(res))
  .catch(error => console.error(error));

function print(result) {
  console.log('Directories are %s', result.same ? 'identical' : 'different')

  console.log('Statistics - equal entries: %s, distinct entries: %s, left only entries: %s, right only entries: %s, differences: %s',
    result.equal, result.distinct, result.left, result.right, result.differences)

  result.diffSet.forEach(dif => console.log('Difference - path: %s, name1: %s, type1: %s, name2: %s, type2: %s, state: %s',
    dif.relativePath, dif.name1, dif.type1, dif.name2, dif.type2, dif.state))


import { compare, compareSync, Options, Result } from "dir-compare";
const path1 = '...';
const path2 = '...';
const options: Options = { compareSize: true };

const res: Result = compareSync(path1, path2, options);

compare(path1, path2, options)
  .then(res => console.log(res))
  .catch(error => console.error(error));


compare(path1: string, path2: string, options?: Options): Promise<Result>
compareSync(path1: string, path2: string, options?: Options): Result

More details can be found in the reference documentation:

Common options:

Glob patterns

Minimatch patterns are used to include/exclude files to be compared.

The pattern is matched against the relative path of the entry being compared.

Following examples assume we are comparing two dir-compare code bases.

const options = { 
  excludeFilter: ".git,node_modules",   //  exclude git and node modules directories  
  excludeFilter: "expected"         ,   //  exclude '/tests/expected' directory  
  excludeFilter: "/tests/expected"  ,   //  exclude '/tests/expected' directory  
  excludeFilter: "**/expected"      ,   //  exclude '/tests/expected' directory  
  excludeFilter: "**/tests/**/*.js" ,   //  exclude all js files in '/tests' directory and subdirectories  

  includeFilter: "*.js,*.yml"       ,   //  include js and yaml files  
  includeFilter: "/tests/**/*.js"   ,   //  include all js files in '/tests' directory and subdirectories  
  includeFilter: "**/tests/**/*.ts"     //  include all js files in '/tests' directory and subdirectories  

This behavior can be changed with Glob filter extensions.

Symbolic links

Unless compareSymlink option is used, symbolic links are resolved and any comparison is applied to the file/directory they point to.

Circular loops are handled by breaking the loop as soon as it is detected.

Version 1.x treats broken links as ENOENT: no such file or directory.
Since 2.0 they are treated as a special type of entry - broken-link - and are available as stats (totalBrokenLinks, distinctBrokenLinks, ...).

Using compareSymlink option causes dircompare to check symlink values for equality. In this mode two entries with identical names are considered different if

  • one is symlink, the other is not
  • both are symlinks but point to different locations

These rules are applied in addition to the other comparison modes; ie. by content, by size...

If entries are different because of symlinks, reason will be different-symlink. Also statistics summarize differences caused by symbolic links.

Handling permission denied errors

Unreadable files or directories are normally reported as errors. The comparison will be interrupted with an EACCES exception. This behavior can be altered with Options.handlePermissionDenied.

Extension points

File content comparators

By default file content is binary compared. As of version 1.5.0 custom file comparison handlers may be specified.

Custom handlers are specified by compareFileSync and compareFileAsync options which correspond to dircompare.compareSync() or dircompare.compare() methods.

A couple of handlers are included in the library:

  • binary sync compare - dircompare.fileCompareHandlers.defaultFileCompare.compareSync
  • binary async compare - dircompare.fileCompareHandlers.defaultFileCompare.compareAsync
  • text sync compare - dircompare.fileCompareHandlers.lineBasedFileCompare.compareSync
  • text async compare - dircompare.fileCompareHandlers.lineBasedFileCompare.compareAsync

Use defaultFileCompare as an example to create your own.

Ignore line endings and white spaces

Line based comparator can be used to ignore line ending and white space differences.

const dircompare = require('dir-compare');

const options = {
  compareContent: true,
  compareFileSync: dircompare.fileCompareHandlers.lineBasedFileCompare.compareSync,
  compareFileAsync: dircompare.fileCompareHandlers.lineBasedFileCompare.compareAsync,
  ignoreLineEnding: true,      // Ignore crlf/lf line ending differences
  ignoreWhiteSpaces: true,     // Ignore white spaces at the beginning and end of a line (similar to 'diff -b')
  ignoreAllWhiteSpaces: true,  // Ignore all white space differences (similar to 'diff -w')
  ignoreEmptyLines: true       // Ignores differences caused by empty lines (similar to 'diff -B')

const path1 = '...';
const path2 = '...';
const res = dircompare.compareSync(path1, path2, options);

dircompare.compare(path1, path2, options)
.then(res => console.log(res))

Glob filter

The current implementation of the glob filter uses minimatch and is based on includeFilter and excludeFilter options. While it is meant to fit most use cases, some scenarios are not addressed.

Use filterHandler option to alter this behavior.

The following example demonstrates how to include only files with a specific extension in our comparison.

import { Options, compareSync, Result, FilterHandler, Entry, filterHandlers } from 'dir-compare'
import { extname } from 'path'

var d1 = '...';
var d2 = '...';

const filterByfileExtension: FilterHandler = (entry: Entry, relativePath: string, options: Options): boolean => {
  if (!options.fileExtension) {
    // Fallback on the default 'minimatch' implementation
    return filterHandlers.defaultFilterHandler(entry, relativePath, options)

  return options.fileExtension === extname(entry.name)

const options: Options = {
  compareSize: true,
  fileExtension: '.txt',
  filterHandler: filterByfileExtension

const res: Result = compareSync(d1, d2, options)

For reference, the default minimatch filter can be found in defaultFilterHandler which is exposed by filterHandlers property.

Implement .gitignore filter

Globby library provides the functionality to parse and apply .gitignore rules. This is a sample implementation that uses globby and dir-compare filter extension.


import { Options, compareSync, Result} from 'dir-compare'
import { getGitignoreFilter } from './gitignoreFilter.js'

var d1 = '...';
var d2 = '...';

const options: Options = {
  compareSize: true,
  filterHandler: getGitignoreFilter(d1, d2),
  includeFilter: '*.js'  // if present, regular filters are applied after .gitignore rules.

const res: Result = compareSync(d1, d2, options)

Name comparators

If default name comparison is not enough, custom behavior can be specified with compareNameHandler option. Following example adds the possibility to ignore file extensions.

import { Options, compare } from 'dir-compare'
import path from 'path'

const options: Options = {
    compareSize: false,                    // compare only name by disabling size and content criteria
    compareContent: false,
    compareNameHandler: customNameCompare, // new name comparator used to ignore extensions
    ignoreExtension: true,                 // supported by the custom name compare below

function customNameCompare(name1: string, name2: string, options: Options) {
    if (options.ignoreCase) {
        name1 = name1.toLowerCase()
        name2 = name2.toLowerCase()
    if (options.ignoreExtension) {
        name1 = path.basename(name1, path.extname(name1))
        name2 = path.basename(name2, path.extname(name2))
    return ((name1 === name2) ? 0 : ((name1 > name2) ? 1 : -1))

const path1 = '/tmp/a';
const path2 = '/tmp/b';

const res = compare(path1, path2, options).then(res => {
    console.log(`Same: ${res.same}`)
    if (!res.diffSet) {
    res.diffSet.forEach(dif => console.log(`${dif.name1} ${dif.name2} ${dif.state}`))

// Outputs
// icon.svg icon.png equal
// logo.svg logo.jpg equal

For reference, the default name comparator can be found in defaultNameCompare which is exposed by compareNameHandlers property.

Result builder

Result builder is called for each pair of entries encountered during comparison. Its purpose is to append entries in diffSet and eventually update statistics object with new stats.

If needed it can be replaced with custom implementation.

const dircompare = require("dircompare")

const customResultBuilder = function (entry1, entry2, state, level, relativePath, options, statistics, diffSet, reason) {

const options = {
    compareSize: true,
    resultBuilder: customResultBuilder
const res = dircompare.compareSync('...', '...', options)

The default builder can be used as an example.

UI tools


  • v5.0.0 Breaking changes:

    • skipSubdirs option has slightly different behavior. More details in #77
  • v4.2.0

    • Updated dependencies
    • Increased test coverage
  • v4.1.0

  • v4.0.0

    • Switched project to typescript
    • Async comparator improvements when comparing large directory structures
      • Heap usage has decreased 3x compared to previous version
      • Works 2x faster when comparing by content
      • Better concurrency. UI apps will be more responsive while comparison is ongoing

    Breaking changes:

    • Using this library to compare two files will ignore the name of the files. More details in #48
    • Removed support for node 8, 9
  • v3.3.0 Added skipEmptyDirs option

  • v3.2.0 Handle permission denied errors

  • v3.1.0 Added ignoreAllWhiteSpaces and ignoreEmptyLines options

  • v3.0.0 Moved CLI component into separate project dir-compare-cli

  • v2.4.0 New option to customize file/folder name comparison

  • v2.3.0 Fixes

  • v2.1.0 Removed bluebird dependency

  • v2.0.0

    • New option to compare symlinks.
    • New field indicating reason for two entries being distinct.
    • Improved command line output format.
    • Tests are no longer part of published package.
    • Generated Api documentation.

    Breaking changes:

    • Broken links are no longer treated as errors. As a result there are new statistics (leftBrokenLinks, rightBrokenLinks, distinctBrokenLinks, totalBrokenLinks) and new entry type - broken-link. Details in Symbolic links.
    • Typescript correction: new interface Result replaced Statistics.
  • v1.8.0

    • globstar patterns
    • typescript corrections
    • removed support for node 0.11, 0.12, iojs
  • v1.7.0 performance improvements

  • v1.6.0 typescript support

  • v1.5.0 added option to ignore line endings and white space differences

  • v1.3.0 added date tolerance option

  • v1.2.0 added compare by date option

  • v1.1.0

    • detect symlink loops
    • improved color scheme for command line utility
  • v1.0.0

    • asynchronous comparison
    • new library options: noDiffSet, resultBuilder
    • new statistics: distinctFiles, equalFiles, leftFiles, rightFiles, distinctDirs, equalDirs, leftDirs, rightDirs
    • new --async command line option
    • Fix for https://github.com/tj/commander.js/issues/125
  • v0.0.3 Fix file ordering issue for newer node versions

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