A simple and beautiful text diff viewer component made with Diff and React.
Inspired from Github diff viewer, it includes features like split view, inline view, word diff, line highlight and more. It is highly customizable and it supports almost all languages.
Most credit goes to Pranesh Ravi who created the original diff viewer. I've just made a few modifications and updated the dependencies so they work with modern stacks.
yarn add react-diff-viewer
# or
npm i react-diff-viewer
# or
pnpm add react-diff-viewerimport React, { PureComponent } from 'react';
import ReactDiffViewer from 'react-diff-viewer';
const oldCode = `
const a = 10
const b = 10
const c = () => console.log('foo')
if(a > 10) {
console.log('bar')
}
console.log('done')
`;
const newCode = `
const a = 10
const boo = 10
if(a === 10) {
console.log('bar')
}
`;
class Diff extends PureComponent {
render = () => {
return (
<ReactDiffViewer oldValue={oldCode} newValue={newCode} splitView={true} />
);
};
}| Prop | Type | Default | Description |
|---|---|---|---|
| oldValue | string |
'' |
Old value as string. |
| newValue | string |
'' |
New value as string. |
| splitView | boolean |
true |
Switch between unified and split view. |
| disableWordDiff | boolean |
false |
Show and hide word diff in a diff line. |
| compareMethod | DiffMethod |
DiffMethod.CHARS |
JsDiff text diff method used for diffing strings. Check out the guide to use different methods. |
| renderGutter | (diffData) => ReactNode |
undefined |
Function that can be used to render an extra gutter with various information next to the line number. |
| hideLineNumbers | boolean |
false |
Show and hide line numbers. |
| renderContent | function |
undefined |
Render Prop API to render code in the diff viewer. Helpful for syntax highlighting |
| onLineNumberClick | function |
undefined |
Event handler for line number click. (lineId: string) => void |
| highlightLines | array[string] |
[] |
List of lines to be highlighted. Works together with onLineNumberClick. Line number are prefixed with L and R for the left and right section of the diff viewer, respectively. For example, L-20 means 20th line in the left pane. To highlight a range of line numbers, pass the prefixed line number as an array. For example, [L-2, L-3, L-4, L-5] will highlight the lines 2-5 in the left pane. |
| showDiffOnly | boolean |
true |
Shows only the diffed lines and folds the unchanged lines |
| extraLinesSurroundingDiff | number |
3 |
Number of extra unchanged lines surrounding the diff. Works along with showDiffOnly. |
| codeFoldMessageRenderer | function |
Expand {number} of lines ... |
Render Prop API to render code fold message. |
| styles | object |
{} |
To override style variables and styles. Learn more about overriding styles |
| useDarkTheme | boolean |
true |
To enable/disable dark theme. |
| leftTitle | string |
undefined |
Column title for left section of the diff in split view. This will be used as the only title in inline view. |
| rightTitle | string |
undefined |
Column title for right section of the diff in split view. This will be ignored in inline view. |
| linesOffset | number |
0 |
Number to start count code lines from. |
resetCodeBlocks() - Resets the expanded code blocks to it's initial state. Return true on successful reset and false during unsuccessful reset.
Syntax highlighting is a bit tricky when combined with diff. Here, React Diff Viewer provides a simple render prop API to handle syntax highlighting. Use renderContent(content: string) => JSX.Element and your favorite syntax highlighting library to achieve this.
An example using Prism JS
// Load Prism CSS
<link
href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.15.0/prism.min.css"
/>
// Load Prism JS
<script src="https://cdnjs.cloudflare.com/ajax/libs/prism/1.15.0/prism.min.js"></script>import React, { PureComponent } from 'react';
import ReactDiffViewer from 'react-diff-viewer';
const oldCode = `
const a = 10
const b = 10
const c = () => console.log('foo')
if(a > 10) {
console.log('bar')
}
console.log('done')
`;
const newCode = `
const a = 10
const boo = 10
if(a === 10) {
console.log('bar')
}
`;
class Diff extends PureComponent {
highlightSyntax = (str) => (
<pre
style={{ display: 'inline' }}
dangerouslySetInnerHTML={{
__html: Prism.highlight(str, Prism.languages.javascript),
}}
/>
);
render = () => {
return (
<ReactDiffViewer
oldValue={oldCode}
newValue={newCode}
splitView={true}
renderContent={this.highlightSyntax}
/>
);
};
}Different styles of text block diffing are possible by using the enums corresponding to variou JsDiff methods (learn more). The supported methods are as follows.
enum DiffMethod {
CHARS = 'diffChars',
WORDS = 'diffWords',
WORDS_WITH_SPACE = 'diffWordsWithSpace',
LINES = 'diffLines',
TRIMMED_LINES = 'diffTrimmedLines',
SENTENCES = 'diffSentences',
CSS = 'diffCss',
}import React, { PureComponent } from 'react';
import ReactDiffViewer, { DiffMethod } from 'react-diff-viewer';
const oldCode = `
{
"name": "Original name",
"description": null
}
`;
const newCode = `
{
"name": "My updated name",
"description": "Brand new description",
"status": "running"
}
`;
class Diff extends PureComponent {
render = () => {
return (
<ReactDiffViewer
oldValue={oldCode}
newValue={newCode}
compareMethod={DiffMethod.WORDS}
splitView={true}
/>
);
};
}React Diff Viewer uses emotion for styling. It also offers a simple way to override styles and style variables. You can supply different variables for both light and dark themes. Styles will be common for both themes.
Below are the default style variables and style object keys.
// Default variables and style keys
const defaultStyles = {
variables: {
light: {
diffViewerBackground: '#fff',
diffViewerColor: '#212529',
addedBackground: '#e6ffed',
addedColor: '#24292e',
removedBackground: '#ffeef0',
removedColor: '#24292e',
wordAddedBackground: '#acf2bd',
wordRemovedBackground: '#fdb8c0',
addedGutterBackground: '#cdffd8',
removedGutterBackground: '#ffdce0',
gutterBackground: '#f7f7f7',
gutterBackgroundDark: '#f3f1f1',
highlightBackground: '#fffbdd',
highlightGutterBackground: '#fff5b1',
codeFoldGutterBackground: '#dbedff',
codeFoldBackground: '#f1f8ff',
emptyLineBackground: '#fafbfc',
gutterColor: '#212529',
addedGutterColor: '#212529',
removedGutterColor: '#212529',
codeFoldContentColor: '#212529',
diffViewerTitleBackground: '#fafbfc',
diffViewerTitleColor: '#212529',
diffViewerTitleBorderColor: '#eee',
},
dark: {
diffViewerBackground: '#2e303c',
diffViewerColor: '#FFF',
addedBackground: '#044B53',
addedColor: 'white',
removedBackground: '#632F34',
removedColor: 'white',
wordAddedBackground: '#055d67',
wordRemovedBackground: '#7d383f',
addedGutterBackground: '#034148',
removedGutterBackground: '#632b30',
gutterBackground: '#2c2f3a',
gutterBackgroundDark: '#262933',
highlightBackground: '#2a3967',
highlightGutterBackground: '#2d4077',
codeFoldGutterBackground: '#21232b',
codeFoldBackground: '#262831',
emptyLineBackground: '#363946',
gutterColor: '#464c67',
addedGutterColor: '#8c8c8c',
removedGutterColor: '#8c8c8c',
codeFoldContentColor: '#555a7b',
diffViewerTitleBackground: '#2f323e',
diffViewerTitleColor: '#555a7b',
diffViewerTitleBorderColor: '#353846',
}
},
diffContainer?: {}, // style object
diffRemoved?: {}, // style object
diffAdded?: {}, // style object
marker?: {}, // style object
emptyGutter?: {}, // style object
highlightedLine?: {}, // style object
lineNumber?: {}, // style object
highlightedGutter?: {}, // style object
contentText?: {}, // style object
gutter?: {}, // style object
line?: {}, // style object
wordDiff?: {}, // style object
wordAdded?: {}, // style object
wordRemoved?: {}, // style object
codeFoldGutter?: {}, // style object
codeFold?: {}, // style object
emptyLine?: {}, // style object
content?: {}, // style object
titleBlock?: {}, // style object
splitView?: {}, // style object
}To override any style, just pass the new style object to the styles prop. New style will be computed using Object.assign(default, override).
For keys other than variables, the value can either be an object or string interpolation.
import React, { PureComponent } from 'react';
import ReactDiffViewer from 'react-diff-viewer';
const oldCode = `
const a = 10
const b = 10
const c = () => console.log('foo')
if(a > 10) {
console.log('bar')
}
console.log('done')
`;
const newCode = `
const a = 10
const boo = 10
if(a === 10) {
console.log('bar')
}
`;
class Diff extends PureComponent {
highlightSyntax = (str) => (
<span
style={{ display: 'inline' }}
dangerouslySetInnerHTML={{
__html: Prism.highlight(str, Prism.languages.javascript),
}}
/>
);
render = () => {
const newStyles = {
variables: {
dark: {
highlightBackground: '#fefed5',
highlightGutterBackground: '#ffcd3c',
},
},
line: {
padding: '10px 2px',
'&:hover': {
background: '#a26ea1',
},
},
};
return (
<ReactDiffViewer
styles={newStyles}
oldValue={oldCode}
newValue={newCode}
splitView={true}
renderContent={this.highlightSyntax}
/>
);
};
}After cloning this package in your local and then just cd into root directory of project and then do:
yarn install
yarn build # or use yarn build:watchNow go into the Keploy UI(assuming you have cloned it already!) folder and open package.json where you will see this:
"react-diff-viewer": "github:keploy/react-diff-viewer"Repalce it's path to your local relative path of cloned react-diff-viewer for example like this:
"react-diff-viewer": "file:../../react-diff-viewer"And do
npm iNow you should be able to use your local react-diff-viewer in your UI(locally). Whatever change you do locally in your react-diff-viewer will be used in your Keploy UI(locally).. You can confirm this by checking into node modules you will be able to see react-diff-viewer there.
That's it! Please ping on our slack channel for any problems :)...And What are you waiting for JUST raise a PR!
MIT