Code Snippet Ember Helper

This is an Ember helper (and ember-cli addon) that lets you render code snippets within your app. The code snippets can live in their own dedicated files or you can extract blocks of code from your application itself.

Compatibility

• Ember.js v2.18 or above
• Ember CLI v2.13 or above
• Node.js v8 or above

Installation

ember install ember-code-snippet

Usage

Defining snippets

There are two ways to store your code snippets. You can use either or both together.

With separate snippet files

Create a new "snippets" directory at the top level of your ember-cli application or addon, and place the code snippets you'd like to render in their own files inside it. They will be identified by filename. So if you create the file snippets/sample-template.hbs, you can refer to it when using the get-code-snippet helper as sample-template.hbs.

You can choose to load snippet files from different paths by passing an option to new EmberApp in your ember-cli-build.js:

var app = new EmberApp({
  snippetPaths: ['snippets']
});

If you want to use snippets located in an addon's dummy application, add the dummy app path to snippetPaths:

var app = new EmberAddon({
  snippetPaths: ['tests/dummy/app']
});

From within your application source

In any file under your app tree, annotate the start and end of a code snippet block by placing comments like this:

// BEGIN-SNIPPET my-nice-example
function sample(){
  return 42;
};
// END-SNIPPET

The above is a Javascript example, but you can use any language's comment format. We're just looking for lines that match /\bBEGIN-SNIPPET\s+(\S+)\b/ and /\bEND-SNIPPET\b/.

The opening comment must include a name. The helper will identify these snippets using the names you specified plus the file extension of the file in which they appeared.

You can also define your own regex to find snippets. Just use the snippetRegexes option:

var app = new EmberAddon({
 snippetRegexes: {
   begin: /{{#element-example\sname=\"(\S+)\"/,
   end: /{{\/element-example}}/,
 }
});

In the regex above everything in the element-example component block will be a snippet! Just make sure the first regex capture group is the name of the snippet.

You can choose which paths will be searched for inline snippets by settings the snippetSearchPaths option when creating your application in ember-cli-build.js:

var app = new EmberApp({
  snippetSearchPaths: ['app', 'other']
});

By default, the file extension from the containing file will automatically be included in the snippet name. For instance, the example above has BEGIN-SNIPPET my-nice-example in the JS source, and is subsequently referenced as "my-nice-example.js". To disable this behavior, use the includeFileExtensionInSnippetNames option:

var app = new EmberApp({
  includeFileExtensionInSnippetNames: false
});

Helper usage

After you have defined your snippets, you can use the get-code-snippet helper to get the snippet data for rendering: {{get-code-snippet "my-nice-example.js"}}. The returned value will be a JavaScript object with the following properties:

• source: the source code extracted from the given snippet
• language: the snippets language, following the naming conventions of the popular prism.js library, e.g. handlebars for Ember templates
• extension: the file extension of the file containing the given snippet

By default, the helper will try to unindent the code block by removing whitespace characters from the start of each line until the code bumps up against the edge. You can disable this with:

{{get-code-snippet "my-nice-example.js" unindent=false}}

The following example will render a <pre> tag with a given code snippet:

{{#let (get-code-snippet "static.hbs") as |snippet|}}
  <pre class={{snippet.language}}>{{snippet.source}}</pre>
{{/let}}

Syntax Highlighting

This addon does not provide any syntax highlighting capabilities itself, but instead it is designed with composability in mind, so you can add highlighting capabilities with any highlighting library on top of the snippet extraction primitives of this addon. The following is an example of rendering a code snippet using code highlighting provided by the ember-prism addon:

{{#let (get-code-snippet "demo.hbs") as |snippet|}}
  <CodeBlock @language={{snippet.language}}>
    {{snippet.source}}
  </CodeBlock>
{{/let}}

If you want to show multiple snippets, it makes sense to extract that template code into a reusable component. In fact previous versions of ember-code-snippet shipped a code-snippet component, that you can replace now with the new helper and your highlighting library of choice. The following template-only component could replace the previously available component <CodeSnippet @name="demo.hbs" />, again using ember-prism in this case:

{{!-- templates/components/code-snippet.hbs --}}
{{#let (get-code-snippet @name) as |snippet|}}
  <CodeBlock @language={{snippet.language}}>
    {{snippet.source}}
  </CodeBlock>
{{/let}}

JavaScript usage

When you want to use the code snippet functionality from JavaScript, you can import the getCodeSnippet function like this:

import { getCodeSnippet } from 'ember-code-snippet';

Its call signature is similar to the helper invocation: getCodeSnippet(name, unindent = true), and it returns the same POJO as described above.

Contributing

See the Contributing guide for details.

License

This project is licensed under the MIT License.