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3.1.11 • Public • Published


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diff2html generates pretty HTML diffs from git diff or unified diff output.


Table of Contents


  • Supports git and unified diffs

  • Line by line and Side by side diff

  • New and old line numbers

  • Inserted and removed lines

  • GitHub like visual style

  • Code syntax highlight

  • Line similarity matching

  • Easy code selection

Online Example

Go to diff2html



Diff2Html can be used in various ways as listed in the distributions section. The two main ways are:

  • Diff2Html: using the parser and html generator directly from the library gives you complete control about what you can do with the json or html generated.
  • Diff2HtmlUI: using this wrapper makes it easy to inject the html in the DOM and adds some nice features to the diff, like syntax highlight.

Bellow you can find more details and examples about each option.

Diff2Html Usage

To load correctly in the Browser you always need to include the stylesheet in the final HTML.

Import the stylesheet

<!-- CSS -->
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css" />

Diff2Html API

JSON representation of the diff

function parse(diffInput: string, configuration: Diff2HtmlConfig = {}): DiffFile[];

Pretty HTML representation of the diff

function html(diffInput: string | DiffFile[], configuration: Diff2HtmlConfig = {}): string;

Diff2Html Configuration

The HTML output accepts a Javascript object with configuration. Possible options:

  • outputFormat: the format of the output data: 'line-by-line' or 'side-by-side', default is 'line-by-line'
  • drawFileList: show a file list before the diff: true or false, default is true
  • diffStyle: show differences level in each line: word or char, default is word
  • matching: matching level: 'lines' for matching lines, 'words' for matching lines and words or 'none', default is none
  • matchWordsThreshold: similarity threshold for word matching, default is 0.25
  • matchingMaxComparisons: perform at most this much comparisons for line matching a block of changes, default is 2500
  • maxLineSizeInBlockForComparison: maximum number os characters of the bigger line in a block to apply comparison, default is 200
  • maxLineLengthHighlight: only perform diff changes highlight if lines are smaller than this, default is 10000
  • renderNothingWhenEmpty: render nothing if the diff shows no change in its comparison: true or false, default is false
  • compiledTemplates: object with previously compiled templates to replace parts of the html
  • rawTemplates: object with raw not compiled templates to replace parts of the html

    For more information regarding the possible templates look into src/templates

Diff2Html Browser

Import the stylesheet and the library code

<!-- CSS -->
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css" />
<!-- Javascripts -->
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html.min.js"></script>

It will now be available as a global variable named Diff2Html.

document.addEventListener('DOMContentLoaded', () => {
  var diffHtml = global.Diff2Html.html('<Unified Diff String>', {
    drawFileList: true,
    matching: 'lines',
    outputFormat: 'side-by-side',
  document.getElementById('destination-elem-id').innerHTML = diffHtml;

Diff2Html NPM / Node.js Library

const Diff2html = require('diff2html');
const diffJson = Diff2html.parse('<Unified Diff String>');
const diffHtml = Diff2html.html(diffJson, { drawFileList: true });
document.getElementById('destination-elem-id').innerHTML = diffHtml;

Diff2Html Examples

Diff2Html Angular Example

  • Typescript
import * as Diff2Html from 'diff2html';
import { Component, OnInit } from '@angular/core';
export class AppDiffComponent implements OnInit {
  outputHtml: string;
  constructor() {
  ngOnInit() {}
  init() {
    let strInput =
      '--- a/server/vendor/golang.org/x/sys/unix/zsyscall_linux_mipsle.go\n+++ b/server/vendor/golang.org/x/sys/unix/zsyscall_linux_mipsle.go\n@@ -1035,6 +1035,17 @@ func Prctl(option int, arg2 uintptr, arg3 uintptr, arg4 uintptr, arg5 uintptr) (\n \n // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n \n+func Pselect(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {\n+\tr0, _, e1 := Syscall6(SYS_PSELECT6, uintptr(nfd), uintptr(unsafe.Pointer(r)), uintptr(unsafe.Pointer(w)), uintptr(unsafe.Pointer(e)), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)))\n+\tn = int(r0)\n+\tif e1 != 0 {\n+\t\terr = errnoErr(e1)\n+\t}\n+\treturn\n+}\n+\n+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n+\n func read(fd int, p []byte) (n int, err error) {\n \tvar _p0 unsafe.Pointer\n \tif len(p) > 0 {\n';
    let outputHtml = Diff2Html.html(strInput, { drawFileList: true, matching: 'lines' });
    this.outputHtml = outputHtml;
  • HTML
<!DOCTYPE html>
    <div [innerHtml]="outputHtml"></div>
  • .angular-cli.json - Add styles

Diff2Html Vue.js Example

  <div v-html="prettyHtml" />
import * as Diff2Html from 'diff2html';
import 'diff2html/bundles/css/diff2html.min.css';
export default {
  data() {
    return {
        '--- a/server/vendor/golang.org/x/sys/unix/zsyscall_linux_mipsle.go\n+++ b/server/vendor/golang.org/x/sys/unix/zsyscall_linux_mipsle.go\n@@ -1035,6 +1035,17 @@ func Prctl(option int, arg2 uintptr, arg3 uintptr, arg4 uintptr, arg5 uintptr) (\n \n // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n \n+func Pselect(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timespec, sigmask *Sigset_t) (n int, err error) {\n+\tr0, _, e1 := Syscall6(SYS_PSELECT6, uintptr(nfd), uintptr(unsafe.Pointer(r)), uintptr(unsafe.Pointer(w)), uintptr(unsafe.Pointer(e)), uintptr(unsafe.Pointer(timeout)), uintptr(unsafe.Pointer(sigmask)))\n+\tn = int(r0)\n+\tif e1 != 0 {\n+\t\terr = errnoErr(e1)\n+\t}\n+\treturn\n+}\n+\n+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT\n+\n func read(fd int, p []byte) (n int, err error) {\n \tvar _p0 unsafe.Pointer\n \tif len(p) > 0 {\n',
  computed: {
    prettyHtml() {
      return Diff2Html.html(this.diffs, {
        drawFileList: true,
        matching: 'lines',
        outputFormat: 'side-by-side',

Diff2HtmlUI Usage

Simple wrapper to ease simple tasks in the browser such as: code highlight and js effects

  • Invoke Diff2html
  • Inject output in DOM element
  • Enable collapsible file summary list
  • Enable syntax highlight of the code in the diffs

Diff2HtmlUI API

Create a Diff2HtmlUI instance

constructor(targetHTMLElement, diffInput?: string | DiffFile[]) // diff2html-ui, diff2html-ui-slim
constructor(targetHTMLElement, diffInput?: string | DiffFile[], configDiff2HtmlUIConfig = {}, hljs?: HighlightJS) // diff2html-ui-base

Generate and inject in the document the Pretty HTML representation of the diff


Enable extra features


Diff2HtmlUI Configuration

  • synchronisedScroll: scroll both panes in side-by-side mode: true or false, default is true
  • highlight: syntax highlight the code on the diff: true or false, default is true
  • fileListToggle: allow the file summary list to be toggled: true or false, default is true
  • fileListStartVisible: choose if the file summary list starts visible: true or false, default is false

NOTE: All the options from Diff2Html are also valid configurations in Diff2HtmlUI

Diff2HtmlUI Browser

Mandatory HTML resource imports

<!-- CSS -->
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css" />
<!-- Javascripts -->
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html-ui.min.js"></script>


const targetElement = document.getElementById('destination-elem-id');
const configuration = { drawFileList: true, matching: 'lines' };
const diff2htmlUi = new Diff2HtmlUI(targetElement, diffString, configuration);
// or
const diff2htmlUi = new Diff2HtmlUI(targetElement, diffJson, configuration);



Syntax Highlight

<!-- Stylesheet -->
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.13.1/styles/github.min.css" />
<link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css" />
<!-- Javascripts -->
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html-ui.min.js"></script>

Pass the option highlight with value true or invoke diff2htmlUi.highlightCode() after diff2htmlUi.draw().

document.addEventListener('DOMContentLoaded', () => {
  const diffString = `diff --git a/sample.js b/sample.js
index 0000001..0ddf2ba
--- a/sample.js
+++ b/sample.js
@@ -1 +1 @@
-console.log("Hello World!")
+console.log("Hello from Diff2Html!")`;
  const targetElement = document.getElementById('myDiffElement');
  const configuration = { inputFormat: 'json', drawFileList: true, matching: 'lines', highlight: true };
  const diff2htmlUi = new Diff2HtmlUI(targetElement, diffString, configuration);

Collapsable File Summary List

Add the dependencies.

<!-- Javascripts -->
<script type="text/javascript" src="https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html-ui.min.js"></script>

Invoke the Diff2HtmlUI helper Pass the option fileListToggle with value true or invoke diff2htmlUi.fileListToggle() after diff2htmlUi.draw().

document.addEventListener('DOMContentLoaded', () => {
  const targetElement = document.getElementById('myDiffElement');
  var diff2htmlUi = new Diff2HtmlUI(targetElement, lineDiffExample, { drawFileList: true, matching: 'lines' });


1. Out of memory or Slow execution


  • Big files
  • Big lines


  • Disable the line matching algorithm, by setting the option {"matching": "none"} when invoking diff2html


This is a developer friendly project, all the contributions are welcome. To contribute just send a pull request with your changes following the guidelines described in CONTRIBUTING.md. I will try to review them as soon as possible.


Thanks goes to these wonderful people (emoji key):

Rodrigo Fernandes




Ivan Vorontsov


Nick Brewer


Matt Wade


Rafael Cortês


Nuno Teixeira


Koki Oyatsu


James Monger


Wessel van der Pal




Sergey Semenov


Nick Mitchell


Samir Aguiar






Mohamed Akram


Eugene Marcotte


Dima Sabanin


Ben Abbott




Mikko Rantanen





🐛 💻


🛡️ 🚧

Josh Goldberg


This project follows the all-contributors specification. Contributions of any kind welcome!


Copyright 2014-present Rodrigo Fernandes. Released under the terms of the MIT license.


This project is inspired in pretty-diff by Scott González.


npm i diff2html

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