Angular Showdown
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**ngx-showdown is an [Angular](https://angular.io) (>=2) integration for [Showdown](https://github.com/showdownjs/showdown), A `Markdown` to `HTML` converter.**
___
## Demo
* Demo app in [source code](https://github.com/yisraelx/ngx-showdown/blob/master/demo) ([live](http://yisraelx.github.io/ngx-showdown)).
* You can play with it in [Stackblitz](https://stackblitz.com/edit/ngx-showdown) and [Plunker](https://plnkr.co/edit/0j8d9w).
## Install
```bash
$ npm install ngx-showdown --save
```
and install peer dependencies (`@angular/common/http` for `SourceDirective`)
```bash
$ npm install showdown @angular/common @angular/platform-browser --save
```
and install type package of `Showdown` for `TypeScript`
```bash
$ npm install @types/showdown --save-dev
```
## Usage
*For more information and explanations, see the [full documentation](https://yisraelx.github.io/ngx-showdown/docs/index.html).*
### Setup `ShowdownModule` in your app.
Add `ShowdownModule` to `imports` of App.
```typescript
import { NgModule } from '@angular/core';
import { ShowdownModule } from 'ngx-showdown';
@NgModule({
imports: [ ShowdownModule ]
})
export class AppModule {}
```
Or with config (it will init `ShowdownConfig` provider)
```typescript
import { NgModule } from '@angular/core';
import { ShowdownModule } from 'ngx-showdown';
@NgModule({
imports: [ ShowdownModule.forRoot({emoji: true, noHeaderId: true, flavor: 'github'}) ]
})
export class AppModule {}
```
Add `showdown` to [`allowedCommonJsDependencies`](https://angular.io/guide/build#configuring-commonjs-dependencies) in the build config of the `angular.json` file (From angular >= 10).
```json
"build": {
"builder": "@angular-devkit/build-angular:browser",
"options": {
"allowedCommonJsDependencies": [
"showdown"
]
...
}
...
},
```
### Use `ShowdownComponent` in the template
#### Binding to `[value]` property
Bind markdown value to `value` property of showdown component.
```html
```
Bind value and options.
```typescript
import { Component } from '@angular/core';
import * as Showdown from 'showdown';
@Component({
selector: 'some',
template: ''
})
export class SomeComponent {
text: string = `
# h1
## h2
`;
options: Showdown.ShowdownOptions = {...};
// ...
}
```
As directive on anther element
```html
```
#### Markdown in component content
A markdown value in the component content.
```html
# H1
## H2
```
With options
```html
* a
* b
* c
```
As directive on anther element
```html
:showdown:**howdown**
```
#### Load .md content (by `SourceDirective`)
Load markdown content of url source.
```html
```
Bind input url to `src` directive.
```html
**No Url..**
```
*Note: Loading markdown content requires [`HttpClient`](https://angular.io/api/common/http/HttpClient) of [`@angular/common/http`](https://angular.io/api/common/http)*
#### Mixing sources
When both `Content` and `[value]`, It will render `[value]`.
```html
# Content
```
When both `Content` and `[src]`, It will render `Content` and when `src` loads then results will be `src` content.
```html
# Content
```
When both `[value]` and `[src]`, It will render `[value]` and when `src` loads then results will be `src` content.
```html
```
#### Binding options
Bind options object (it init root `ShowdownConfig` and then set the bind `options`)
```typescript
import { Component } from '@angular/core';
import * as Showdown from 'showdown';
@Component({
selector: `some`,
template: ``
})
export class SomeComponent {
text: string = '# Some';
options: Showdown.ShowdownOptions = {noHeaderId: true};
// ...
}
```
Or
```html
# abc
```
Bind single option (it have input properties for all showdown options).
```html
# abc
```
#### Sanitize the convert html output
Sanitize the convert html output by [`DomSanitizer`](https://angular.io/api/platform-browser/DomSanitizer#sanitize).
```html
# Some
Click
__Foo__
```
Also sanitize content of `src` url.
```html
```
### Use `ShowdownPipe` in the template
Transform markdown value of `text` property to html.
```html
{{ text | showdown }}
```
Transform value with options (it init root `ShowdownConfig` and then set the pipe `options`)
```typescript
import { Component } from '@angular/core';
import * as Showdown from 'showdown';
@Component({
selector: 'some',
template: '{{ text | showdown:options }}'
})
export class SomeComponent {
text: string = `
# h1
## h2
`;
options: Showdown.ShowdownOptions = {smartIndentationFix: true};
// ...
}
```
### Use `ShowdownConverter` service
```typescript
import { Injectable } from '@angular/core';
import { ShowdownConverter } from 'ngx-showdown';
@Injectable()
export class SomeService {
constructor(showdownConverter: ShowdownConverter){
console.log(showdownConverter.makeHtml('# Showdown'));
}
}
```
### Set config provider (`ShowdownConfig`)
Set root config that will be injected to [ShowdownComponent](#ShowdownComponent), [ShowdownPipe](#ShowdownPipe), [ShowdownConverter](#ShowdownConverter) when they are created.
```typescript
import { NgModel } from '@angular/core';
import { ShowdownModule, ShowdownConverter } from 'ngx-showdown';
import * as Showdown from 'showdown';
let colorExtension: Showdown.FilterExtension = {
type: 'output',
filter(text: string, converter: ShowdownConverter){
return text.replace('$color', converter.getOption('color') || 'green')
}
};
@NgModel({
imports:[
ShowdownModule.forRoot({
flavor: 'original',
emoji: true,
color: 'red',
extensions: [ colorExtension ]
})
]
})
export class AppModule {}
```
Override the root config provider value.
```typescript
import { Component } from '@angular/core';
import { ShowdownConfig } from 'ngx-showdown';
@Component({
selector: 'some',
template: '# Header',
providers: [ {provide: ShowdownConfig, useValue: {underline: true, emoji: false}} ]
})
export class SomeComponent {}
```
Set the config manually by the converter methods.
```typescript
import { Component } from '@angular/core';
import { ShowdownComponent } from 'ngx-showdown';
import highlightExtension from 'showdown-highlight';
import 'highlight.js/styles/default.css';
@Component({
selector: 'some',
template: '# Header'
})
export class SomeComponent {
constructor(showdownComponent: ShowdownComponent) {
showdownComponent.addExtension(highlightExtension);
showdownComponent.setFlavor('ghost');
showdownComponent.setOptions({emoji: true});
}
}
```
#### Flavor
Set root flavor ([Showdown flavors](https://github.com/showdownjs/showdown/blob/master/README.md#flavors)).
```typescript
import { NgModel } from '@angular/core';
import { ShowdownModule } from 'ngx-showdown';
@NgModel({
imports:[
ShowdownModule.forRoot({flavor: 'github'})
]
})
export class AppModule {}
```
*Note: If `flavor` is not set then the default value is 'vanilla' flavor.*
#### ConverterOptions
Set root ConverterOptions ([Showdown options](https://github.com/showdownjs/showdown/blob/master/README.md#valid-options)).
```typescript
import { NgModel } from '@angular/core';
import { ShowdownModule } from 'ngx-showdown';
@NgModel({
imports:[
ShowdownModule.forRoot({underline: true, emoji: false})
]
})
export class AppModule {}
```
#### Extensions
Set root Extensions ([Showdown extensions](https://github.com/showdownjs/showdown#extensions)).
With extension can be made changes to the `Markdown` input ('lang') and the `Html` output also listen to parse event, you can [make extension](https://github.com/showdownjs/showdown/wiki/Extensions) or [search in npm](https://www.npmjs.com/search?q=keywords:showdown%20extension) for existing extension.
```typescript
import { NgModel } from '@angular/core';
import { ShowdownModule } from 'ngx-showdown';
import * as Showdown from 'showdown';
import highlightExtension from 'showdown-highlight';
import 'highlight.js/styles/default.css';
let someExtension: Showdown.ShowdownExtension = {
type: 'lang',
regex: new RegExp('markdown', 'g'),
replace: 'showdown'
};
@NgModel({
imports: [
ShowdownModule.forRoot({extensions: [ someExtension, highlightExtension ]})
]
})
export class AppModule {}
```
## Troubleshoot
#### Interpolation
Using unescaped `{}` (`{}`) in template causes an template parse error ([@angular/angular/#11859](https://github.com/angular/angular/issues/11859)),
The solution is to use escape chars (html char code etc.),
Anther solution is to override the default [interpolation](https://angular.io/api/core/Component#interpolation).
#### Whitespaces
Angular aot compiler remove whitespaces by default, use [ngPreserveWhitespaces](https://angular.io/api/core/Component#preserving-whitespace) to preserve whitespaces.
```html
* a
* 1
* 2
* b
```
With `ngPreserveWhitespaces`
```
* a
* 1
* 2
* b
```
Without `ngPreserveWhitespaces`
```
* a * 1 * 2
* b
```
#### Indentation
Showdown converter [smartIndentationFix](https://github.com/showdownjs/showdown/wiki/Showdown-options#smartindentationfix) option can fix string indentation problems of es6 template and html.
```typescript
text = `
# A
## B
`;
```
```html
```
With `smartIndentationFix`
```
# A
## B
```
Without `smartIndentationFix`
```
# A
## B
```
## Contribute
**Pull requests are welcome!**
## Development
This project built with [`Angular Cli`](https://angular.io/cli).
Install dependencies
```bash
$ yarn install
```
Run test
```bash
$ yarn test
```
Build for release
```bash
$ yarn build
```
## Credits
This project use [Showdown library](https://github.com/showdownjs/showdown) to convert `Markdown` to `Html`.
## License
Copyright © [Yisrael Eliav](https://github.com/yisraelx),
Licensed under the [MIT license](https://github.com/yisraelx/ngx-showdown/blob/master/LICENSE).