PIMD Highlight plugin

Highlights important parts of a code example.

Example usage

```html +highlight="important-class"
<div class="important-class other-class">
  Lorem ipsum.
</div>
```

Result:

Setup

npm i @pimd/html-injector-plugin @pimd/highlight-plugin

This requires the HTML injector plugin to be loaded first:

// ...
const htmlInjectorPlugin = require("@pimd/html-injector-plugin")
const highlightPlugin = require("@pimd/highlight-plugin")

config.use(htmlInjectorPlugin)
config.use(highlightPlugin)

Using Regular Expressions

Instead of strings, Regular Expressions can be used:

```html +highlight=/important-class/
<div class="important-class other-class">
  Lorem ipsum.
</div>
```

All Regular Expressions supported by JavaScript can be used in PIMD. The example above could also highlight all classes ending with -class:

```html +highlight=/\w+-class/
<div class="important-class other-class">
  Lorem ipsum.
</div>
```

Highlight all occourances

To highlight all occourances, Regular Expressions must be used with the g modifier. Strings in quotation marks will always highlight the first occourance only.

```html +highlight=/my-list-item/g
<ul>
  <li class="my-list-item">
    Item 1
  </li>
  <li class="my-list-item">
    Item 2
  </li>
  <li class="my-list-item">
    Item 3
  </li>
</ul>
```

Highlight in different colors

For some examples it is useful to use different colors to help the reader understanding the code. Multiple highlights can be added comma-separated. Each highlight will be highlighted in a differen color (depending on the theme).

A JavaScript example with a use case for multiple (multi color) highlights:

<input name="number" value="1" type="number">
<button id="increase" type="button">Increase</button>
<script>
  const input = document.querySelector('[name="number"]')
  const button = document.querySelector("#increase")
  button.addEventListener("click", function() {
    input.value = Number.parseInt(input.value) + 1
  })
</script>

The example above would be highlighted with:

```html +highlight=/\[?name="number"\]?/g,/value/g,/id="increase"|#increase/g
<input name="number" value="1" type="number">
<button id="increase" type="button">Increase</button>
<script>
  const input = document.querySelector("[name=number]")
  const button = document.querySelector("#increase")
  button.addEventListener("click", function() {
    input.value = Number.parseInt(input.value) + 1
  })
</script>
```

Copyright

Copyright 2018++ Nico Hagenburger. See MIT-LICENSE for details. Get in touch with @hagenburger on Twitter or open an issue.