diff2html




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

Table of Contents

- Features
- Online Example
- Distributions
- Usage
- Diff Text Input
- Diff2HtmlUI Usage
- Diff2HtmlUI API
- Diff2HtmlUI Configuration
- Diff2HtmlUI Browser
- Diff2HtmlUI Examples
- Diff2Html Usage
- Diff2Html API
- Diff2Html Configuration
- Diff2Html Browser
- Diff2Html NPM / Node.js Library
- Diff2Html Examples
- Troubleshooting
- 1. Out of memory or Slow execution
- Contribute
- Contributors
- License
- Thanks

Features

- 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

Distributions

- jsdelivr CDN
- WebJar
- Node Library
- NPM CLI
- Manually use from jsdelivr or build the project:
- Browser / Bundle
- Parser and HTML Generator
- bundles/js/diff2html.min.js - includes the
diff parser and html generator
- Wrapper and helper adding syntax highlight, synchronized scroll, and other nice features
- bundles/js/diff2html-ui.min.js -
includes the wrapper of diff2html with highlight for all highlight.js supported languages
- bundles/js/diff2html-ui-slim.min.js -
includes the wrapper of diff2html with "the most common" highlight.js supported languages
- bundles/js/diff2html-ui-base.min.js -
includes the wrapper of diff2html without including a highlight.js implementation. You can use it without
syntax highlight or by passing your own implementation with the languages you prefer
- NPM / Node.js library
- ES5
- lib/diff2html.js - includes the diff parser and html
generator
- lib/ui/js/diff2html-ui.js - includes the
wrapper of diff2html with highlight for all highlight.js supported languages
- lib/ui/js/diff2html-ui-slim.js -
includes the wrapper of diff2html with "the most common" highlight.js supported languages
- lib/ui/js/diff2html-ui-base.js
- ES6
- lib-esm/diff2html.js - includes the diff parser
and html generator
- lib/ui/js/diff2html-ui.js - includes the
wrapper of diff2html with highlight for all highlight.js supported languages
- lib/ui/js/diff2html-ui-slim.js -
includes the wrapper of diff2html with "the most common" highlight.js supported languages
- lib/ui/js/diff2html-ui-base.js -
includes the wrapper of diff2html without including a highlight.js implementation. You can use it without
syntax highlight or by passing your own implementation with the languages you prefer

Usage

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

- 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.
- 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.

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

Diff Text Input

diff2html accepts the text contents of a
unified diff or the superset format git
diff (https://git-scm.com/docs/git-diff) (not combined or word diff). To provide multiples files as input just
concatenate the diffs (just like the output of git diff).

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

$3

> Create a Diff2HtmlUI instance

``ts
constructor(target: HTMLElement, diffInput?: string | DiffFile[]) // diff2html-ui, diff2html-ui-slim
constructor(target: HTMLElement, diffInput?: string | DiffFile[], config: Diff2HtmlUIConfig = {}, hljs?: HighlightJS) // diff2html-ui-base
`

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

`ts
draw(): void
`

> Enable extra features

`ts
synchronisedScroll(): void
fileListToggle(startVisible: boolean): void
highlightCode(): void
stickyFileHeaders(): void
`

$3

- 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
- fileContentToggle: allow each file contents to be toggled: true or false, default is true
- stickyFileHeaders: make file headers sticky: true or false, default is true
- All the options from Diff2Html are also valid configurations in Diff2HtmlUI

$3

#### Mandatory HTML resource imports

`html





`

#### Init

`js
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);
`

#### Draw

`js
diff2htmlUi.draw();
`

#### Syntax Highlight

NOTE: The highlight.js css should come before the diff2html css

`html






`

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

`js
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 = { drawFileList: true, matching: 'lines', highlight: true };
const diff2htmlUi = new Diff2HtmlUI(targetElement, diffString, configuration);
diff2htmlUi.draw();
diff2htmlUi.highlightCode();
});
`

When using the auto color scheme, you will need to specify both the light and dark themes for highlight.js to use.

`html
rel="stylesheet"
href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.8.0/styles/github.min.css"
media="screen and (prefers-color-scheme: light)"
/>
rel="stylesheet"
href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.8.0/styles/github-dark.min.css"
media="screen and (prefers-color-scheme: dark)"
/>
`

#### Collapsable File Summary List

> Add the dependencies.

`html


`

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

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

$3

#### Example with plain HTML+CSS+JS

`html






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









`

#### StimulusJS with TypeScript

`ts
import { Controller } from '@hotwired/stimulus';

import { Diff2HtmlUI, Diff2HtmlUIConfig } from 'diff2html/lib/ui/js/diff2html-ui-slim.js';

// Requires npm install highlight.js
import 'highlight.js/styles/github.css';
import 'diff2html/bundles/css/diff2html.min.css';

export default class extends Controller {
connect(): void {
const diff2htmlUi = new Diff2HtmlUI(this.diffElement, this.unifiedDiff, this.diffConfiguration);

diff2htmlUi.draw();
}

get unifiedDiff(): string {
return this.data.get('unifiedDiff') || '';
}

get diffElement(): HTMLElement {
return this.element as HTMLElement;
}

get diffConfiguration(): Diff2HtmlUIConfig {
return {
drawFileList: true,
matching: 'lines',
};
}
}
`

Diff2Html Usage

$3

> JSON representation of the diff

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

> Pretty HTML representation of the diff

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

$3

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
- srcPrefix: add a prefix to all source (before changes) filepaths, default is ''. Should match the prefix used when
generating the diff.
- dstPrefix: add a prefix to all destination (after changes) filepaths, default is ''. Should match the prefix used
when generating the diff
- diffMaxChanges: number of changed lines after which a file diff is deemed as too big and not displayed, default is
undefined
- diffMaxLineLength: number of characters in a diff line after which a file diff is deemed as too big and not
displayed, default is undefined
- diffTooBigMessage: function allowing to customize the message in case of file diff too big (if diffMaxChanges or
diffMaxLineLength is set). Will be given a file index as a number and should return a string.
- 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
- maxLineLengthHighlight: only perform diff changes highlight if lines are smaller than this, default is 10000
- diffStyle: show differences level in each line: 'word' or 'char', default is 'word'
- renderNothingWhenEmpty: render nothing if the diff shows no change in its comparison: true or false, default is
false
- matchingMaxComparisons: perform at most this much comparisons for line matching a block of changes, default is
2500
- maxLineSizeInBlockForComparison: maximum number of characters of the bigger line in a block to apply comparison,
default is 200
- compiledTemplates: object (Hogan.js template values) with previously
compiled templates to replace parts of the html, default is {}. For example:
{ "tag-file-changed": Hogan.compile("MODIFIED") }
- rawTemplates: object (string values) with raw not compiled templates to replace parts of the html, default is {}.
For example: { "tag-file-changed": "MODIFIED" }
> For more information regarding the possible templates look into
> src/templates
- highlightLanguages: Map of extension to language name, used for highlighting. This overrides the default language
detection based on file extensions.
- colorScheme: color scheme to use for the diff, default is light. Possible values are light, dark, and auto
which will use the browser's preferred color scheme.

$3

Import the stylesheet and the library code.

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

`html





`

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

`js
document.addEventListener('DOMContentLoaded', () => {
var diffHtml = Diff2Html.html('', {
drawFileList: true,
matching: 'lines',
outputFormat: 'side-by-side',
});
document.getElementById('destination-elem-id').innerHTML = diffHtml;
});
`

$3

`js
const Diff2html = require('diff2html');
const diffJson = Diff2html.parse('');
const diffHtml = Diff2html.html(diffJson, { drawFileList: true });
console.log(diffHtml);
`

$3

#### Example with Angular

- Typescript

`typescript
import * as Diff2Html from 'diff2html';
import { Component, OnInit } from '@angular/core';

export class AppDiffComponent implements OnInit {
outputHtml: string;
constructor() {
this.init();
}

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

`html











`

- .angular-cli.json - Add styles

`json
"styles": [
"diff2html.min.css"
]
`

#### Example with Vue.js

`vue



`

Troubleshooting

$3

#### Causes:

- Big files
- Big lines

#### Fix:

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

Contribute

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.

Contributors

Thanks goes to these wonderful people (emoji key):

Rodrigo Fernandes 💻	stockmind 💻	Ivan Vorontsov 💻	Nick Brewer 💻	Matt Wade 🐛 💻	Rafael Cortês 💻	Nuno Teixeira 💻
Koki Oyatsu 🐛 💻	James Monger 📖	Wessel van der Pal 🛡️ 💻	jk-kim 💻	Sergey Semenov 🐛 💻	Nick Mitchell 🐛 💻	Samir Aguiar 📖
pubkey 📖 💻	Илья 📖	Mohamed Akram 🐛 📖 💻	Eugene Marcotte 💻	Dima Sabanin 🚧 💻	Ben Abbott 📖	弘树@阿里 🐛 📖
Mikko Rantanen 🐛	Ann 📖	escitalopram 💻	dependabot[bot] 🛡️ 🚧	Josh Goldberg 💻	Aaron 📖	Pierre Grimaud 📖
Adam Jones 📖	Arthur Charguéraud 📖	Pierric Cistac 📖 💻	Civan Yavuzşen 💻	Tim Gates 📖	campersau 💻	dependabot-preview[bot] 💻

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

License

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

Thanks

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

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