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2.3.4 • Public • Published


An Angular2 codeblock highlighting component using Prismjs.



$ jspm i npm:ng2-prism


$ npm i ng2-prism --save


jspm and systemjs

No additional setup necessary.

systemjs only (installed with npm)

Systemjs needs to know the path to ng2-prism and prismjs, along with the typical angular dependencies (including http). Use map, and make sure defaultJSExtensions is set to true. Here is an example config, for use with the angular2 quickstart:

    defaultJSExtensions: true,
    packages: {        
      app: {
        format: 'register'
    map: {
      "angular2": "node_modules/angular2",
      "rxjs": "node_modules/rxjs",
      "ng2-prism": "node_modules/ng2-prism",
      "prismjs": "node_modules/prismjs"
        .then(null, console.error.bind(console));


Import the component:

import {Codeblock} from 'ng2-prism/codeblock';

Import the language definition for your codeblock:

import {Ruby} from 'ng2-prism/languages';

Include the component and language directive in the directives array:

  selector: 'my-component',
  // ...
  directives: [Codeblock, Ruby]

Add a codeblock to the template with the language directive attached:

<codeblock ruby>
  def my_new_method
    p "So Impressive!"

Angular2 Bindings

Use angular bindings like normal for variable output.

<input type="text" [(ngModel)]="name">
// {{name}} will be replaced by whatever is typed in the input
<codeblock javascript>
  if (name === '{{name}}') {
    console.log("Hello, " + name);

If you want to display the binding without processing place a pre tag around any of the braces.

<input type="text" [(ngModel)]="name">
// {{name}} will not be replaced
<codeblock javascript>

Dynamic Loading

Use the src directive to set a file to download as the source code for a codeblock. The language of the codeblock will be determined from the file extension, unless a language is specified.

First, import the Source directive:

import {Codeblock, Source} from 'ng2-prism/codeblock';

Then add it to the list of directives:

  selector: 'my-component',
  // ...
  directives: [Codeblock, Source]

Then use the src attribute on the codeblock in your template:

<!-- automatically loads as javascript -->
<codeblock src="path/to/main.js"></codeblock>
<!-- tries to highlight the downloaded file as typescript -->
<codeblock typescript src="path/to/main.js"></codeblock>

Notes on Dynamic loading:

  • The codeblock will automatically update on changes to src.
  • Updates to src are throttled at 300ms to prevent unnecessary http requests, you can change the time by setting debounceTime on the codeblock, or by providing SourceDebounceTime - more details here
  • The src attribute must have a file extension.
  • Everything inside the dynamic codeblock will be replaced by the contents of the source file.
  • The source contents are treated as text only, not DOM elements. Components, directives, and bindings will not be processed by angular2.
  • The source directive relies on the angular2 Http module. Make sure you have included the HTTP_PROVIDERS when bootstrapping your app.


Add a theme attribute to the codeblock element:

<codeblock javascript theme="dark">
  // dark themed
<codeblock javascript [theme]="selectedTheme">
  // uses whichever theme is currently stored in the selectedTheme variable

Your theme options are:

  • standard
  • coy
  • dark
  • funky
  • okaidia
  • solarizedlight
  • tomorrow
  • twilight

The list of themes is available at runtime with CodeblockComponent.THEMES.


To embed HTML use the language markup.

If you use standard HTML tags, and carefully close each one, you can write it as normal inside a codeblock:

<codeblock markup>
  <ul class="favorites">
    <li>These are</li>
    <li>a few of</li>
    <li>my favorite</li>
If you want to write a fragment of `HTML` with some unmatched tags the angular interpreter is going to fail to load your template. You must change any opening or closing tag angle brackets, <, to the html entity version:
`< => &lt;`
<codeblock markup>
    &lt;title>Angular 2 QuickStart&lt;/title>
    &lt;meta name="viewport" content="width=device-width, initial-scale=1">
    &lt;!-- 1. Load libraries -->
    &lt;!-- IE required polyfills, in this exact order -->
    &lt;script src="node_modules/es6-shim/es6-shim.min.js">&lt;/script>
    &lt;script src="node_modules/systemjs/dist/system-polyfills.js">&lt;/script>

Dynamically loaded files do not have this limitation.

Angular2 Components, such as a codeblock or an ngIf, will be processed by angular before highlighting. If you want to show their preprocessed version in the highlighted section instead of their results they should be escaped:

<!-- Will display 'A' only -->
<codeblock markup>
  <section *ngIf="true" >A</section>
  <section *ngIf="false">B</section>
<!-- Will display both section elements -->
<codeblock markup>
  &lt;section *ngIf="true" >A&lt;/section>
  &lt;section *ngIf="false">B&lt;/section>

If you want to show bindings without processing use the bind method on a local variable assigned to the codeblock:

<codeblock markup #cb>
  {{ cb.bind('expression') }}
// result


You may optionally specify a language attribute instead of using a directive:

<codeblock language="ruby">
  def my_new_method
    p "So Impressive!"

The attribute makes the language easy to change dynamically:

<codeblock [language]="modern ? 'typescript' : 'javascript'">
  import {Component} from 'angular2/core';

Codeblocks without a valid loaded language attribute or directive get everything except syntax highlighting:

  Just normal text
  but themed
  with line numbers
<codeblock language="spanish">
  Eso no es un lenguaje de verdad!

If you choose to use the language attribute the language must still be imported, but you do not have to list it in the directives array because the template does not need to know about it.

All languages are automatically loaded when any language is imported from ng2-prism/languages. To import only the language(s) you want:

// if you want the directive:
import {Ruby} from 'ng2-prism/languages/ruby';
// If you just want the language:
import 'ng2-prism/languages/ruby';

Line Numbers

Ng2-prism automatically adds line numbers to codeblocks. To disable them bind a lineNumbers attribute to false:

<codeblock [lineNumbers]="false"></codeblock>
<codeblock [lineNumbers]="someBooleanExpression"></codeblock>


Use the shell attribute to display a shell prompt. Pass in the type of shell, either bash or powershell.

<codeblock shell="bash">
<codeblock shell="powershell">

The language attribute is ignored on shell codeblocks.

The default theme for shells is okaidia.


Change the prompt to whatever you want:

<codeblock shell="bash" prompt="#">cd ..</codeblock>
# cd ..
<codeblock shell="bash" prompt="[user@host] $">cd ..</codeblock>
[user@host] $ cd ..


Shells can have certain lines treated as console output, so they don't have a prompt. Use the outputLines attribute. It accepts a comma-separated list of lines or line ranges:

<codeblock shell="bash" outputLines="2,4,5,7-10">
  cd ../..
  This is output
  mkdir hello
  so is
  rm -rf hello
  more output
  more output
  more output
  more output
$ cd ../..
  This is output
$ mkdir hello
  so is
$ rm -rf hello
  more output
  more output
  more output
  more output



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