Angular Highlight.js
[](https://ngx-highlight.netlify.com/)
[](https://stackblitz.com/edit/ngx-highlightjs)
[](https://www.npmjs.com/package/ngx-highlightjs)
[](https://github.com/MurhafSousli/ngx-highlightjs/actions?query=workflow%3Atests)
[](https://www.npmjs.com/package/ngx-highlightjs)
[](https://www.npmjs.com/package/ngx-highlightjs)
[](https://bundlephobia.com/result?p=ngx-highlightjs)
[](/LICENSE)
Instant code highlighting, auto-detect language, super easy to use
___
## Table of Contents
- [Live Demo](https://ngx-highlight.netlify.com/) | [Stackblitz](https://stackblitz.com/edit/ngx-highlightjs)
- [Installation](#installation)
- [Usage](#usage)
- [Development](#development)
- [Issues](#issues)
- [Author](#author)
- [More plugins](#more-plugins)
## Installation
Install with **NPM**
```bash
npm i ngx-highlightjs
```
## Usage
### Import `HighlightModule` in your app
```typescript
import { HighlightModule, HIGHLIGHT_OPTIONS } from 'ngx-highlightjs';
@NgModule({
imports: [
HighlightModule
],
providers: [
{
provide: HIGHLIGHT_OPTIONS,
useValue: {
fullLibraryLoader: () => import('highlight.js'),
}
}
],
})
export class AppModule { }
```
> Note: This will add highlight.js library including all languages to your bundle.
To avoid import everything from highlight.js library, you should import each language you want to highlight manually.
### Import only the core library and the needed highlighting languages
```typescript
import { HighlightModule, HIGHLIGHT_OPTIONS } from 'ngx-highlightjs';
@NgModule({
imports: [
HighlightModule
],
providers: [
{
provide: HIGHLIGHT_OPTIONS,
useValue: {
coreLibraryLoader: () => import('highlight.js/lib/core'),
lineNumbersLoader: () => import('highlightjs-line-numbers.js'), // Optional, only if you want the line numbers
languages: {
typescript: () => import('highlight.js/lib/languages/typescript'),
css: () => import('highlight.js/lib/languages/css'),
xml: () => import('highlight.js/lib/languages/xml')
},
themePath: 'path-to-theme.css' // Optional, and useful if you want to change the theme dynamically
}
}
],
})
export class AppModule { }
```
### HighlightOptions API
| Name | Description |
|-------------------|-------------------------------------------------------------------------------------------------------------------------|
| fullLibraryLoader | A function that returns a promise that loads `highlight.js` full script |
| coreLibraryLoader | A function that returns a promise that loads `highlight.js` core script |
| lineNumbersLoader | A function that returns a promise that loads `line-numbers` script which adds line numbers to the highlight code |
| languages | The set of languages to register |
| config | Set highlight.js config, see [configure-options](http://highlightjs.readthedocs.io/en/latest/api.html#configure-option) |
| themePath | The path to highlighting theme CSS file |
> **NOTE:** Since the update of highlight.js@v10.x.x, should use `coreLibraryLoader: () => import('highlight.js/lib/core')` instead of `coreLibraryLoader: () => import('highlight.js/lib/highlight')`
### Import highlighting theme
**In version >=6.1.0**, A new way is available to load the theme dynamically! this is **OPTIONAL**, you can still use the traditional way.
**Dynamic way**
Set the theme path in the global config, this makes it possible to change the theme on the fly, which is useful if you have light and dark theme in your app.
```ts
providers: [
{
provide: HIGHLIGHT_OPTIONS,
useValue: {
// ...
themePath: 'assets/styles/solarized-dark.css'
}
}
]
```
If you want to import it from the app dist folder, then copy the themes you want to your `assets` directory, or you can just use a CDN link to the theme.
When switching between the app themes you need to call the `setTheme(path)` from the `HighlightLoader` service.
```ts
import { HighlightLoader } from 'ngx-highlightjs';
export class AppComponent {
constructor(private hljsLoader: HighlightLoader) {
}
// Assume you have a callback function when your app theme is changed
onAppThemeChange(appTheme: 'dark' | 'light') {
this.hljsLoader.setTheme(appTheme === 'dark' ? 'assets/styles/solarized-dark.css' : 'assets/styles/solarized-light.css');
}
}
```
> You can still use the traditional way
**Traditional way**
To import highlight.js theme from the node_modules directory in `angular.json`
```
"styles": [
"styles.css",
"../node_modules/highlight.js/styles/github.css",
]
```
Or directly in `src/style.scss`
```css
@import '~highlight.js/styles/github.css';
```
_[List of all available themes from highlight.js](https://github.com/isagalaev/highlight.js/tree/master/src/styles)_
### Use highlight directive
The following line will highlight the given code and append it to the host element
```html
```
[Demo stackblitz](https://stackblitz.com/edit/ngx-highlightjs)
## Options
| Name | Type | Description |
|-------------------|-----------------|------------------------------------------------------------------------------------------------------------|
| **[highlight]** | string | Accept code string to highlight, default `null` |
| **[languages]** | string[] | An array of language names and aliases restricting auto detection to only these languages, default: `null` |
| **[lineNumbers]** | boolean | A flag that indicates adding line numbers to highlighted code element |
| **(highlighted)** | HighlightAutoResult | Stream that emits the result object when element is highlighted |
### NOTE
In Angular 10, when building your project, you might get a warning `WARNING in ... CommonJS or AMD dependencies can cause optimization bailouts.`
To avoid this warning, add the following in your `angular.json`
```json
{
"projects": {
"project-name": {
"architect": {
"build": {
"options": {
"allowedCommonJsDependencies": [
"highlight.js"
]
}
}
}
}
}
}
```
Read more about [CommonJS dependencies configuration](https://angular.io/guide/build#configuring-commonjs-dependencies)
## Plus package
In version >= 4, a new sub-package were added with the following features:
- Highlight gists using gists API
- Highlight code directly from URL
### Usage
```typescript
import { HighlightPlusModule } from 'ngx-highlightjs/plus';
@NgModule({
imports: [
HighlightPlusModule
]
})
export class AppModule {
}
```
### Highlight a gist file
1. Use `[gist]` directive with the gist id to get the response through the output `(gistLoaded)`.
2. Once `(gistLoaded)` emits, you will get access to the gist response.
3. Use `gistContent` pipe to extract the file content from gist response using gist file name.
**Example:**
```html
```
### Highlight all gist files
To loop over `gist?.files`, use `keyvalue` pipe to pass file name into `gistContent` pipe.
**Example:**
```html
```
### Highlight code from URL directly
Use the pipe `codeFromUrl` with the `async` pipe together to get the code text from a raw URL.
**Example:**
```html
```
## Development
This project uses Angular CLI to build the package.
```bash
$ ng build ngx-highlightjs
```
## Issues
If you identify any errors in the library, or have an idea for an improvement, please open an [issue](https://github.com/MurhafSousli/ngx-highlightjs/issues).
## Author
**Murhaf Sousli**
- [github/murhafsousli](https://github.com/MurhafSousli)
- [twitter/murhafsousli](https://twitter.com/MurhafSousli)
## More plugins
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- [ngx-sharebuttons](https://github.com/MurhafSousli/ngx-sharebuttons)
- [ngx-gallery](https://github.com/MurhafSousli/ngx-gallery)
- [ngx-progressbar](https://github.com/MurhafSousli/ngx-progressbar)
- [ngx-bar-rating](https://github.com/MurhafSousli/ngx-bar-rating)
- [ngx-disqus](https://github.com/MurhafSousli/ngx-disqus)
- [ngx-wordpress](https://github.com/MurhafSousli/ngx-wordpress)
- [ngx-teximate](https://github.com/MurhafSousli/ngx-teximate)