gatsby-remark-code-headers

Adds a customizeable header, like a filename, to code blocks for Gatsby.js.

See this plugin being used live at victorzhou.com (source code).

Installation

You must be already using gatsby-transformer-remark. To install, run

$ npm install --save-dev gatsby-remark-code-headers

Then, in gatsby-config.js, update your options for gatsby-transformer-remark:

plugins: [
  {
    resolve: 'gatsby-transformer-remark',
    options: {
      plugins: [
        {
          resolve: 'gatsby-remark-code-headers',
          options: {
            className: 'optional-custom-class-name'
          }
        }
      ]
    }
  }
]

Usage

In your Markdown file, add a header comment to the first line of any code block:

### Code
```js
// Header: filename.js
console.log('This is filename.js');
```
```python
# Header: This is a Python file
print('Hello World!')
```

The header comment must be formatted exactly like one of the examples above. This plugin will replace the header comment with HTML for the header. It effectively transforms the above markdown into this:

### Code
<div class="gatsby-code-header"><h5>filename.js</h5></div>
```js
console.log('This is filename.js');
```
<div class="gatsby-code-header"><h5>This is a Python file</h5></div>
```python
print('Hello World!')
```

Styling

Once your integration works, you’ll probably want to style the code header. Here’s some example CSS you can use as a starting point:

.gatsby-code-header {
  margin: 10px 0 0 0;
}
.gatsby-code-header h5 {
  display: inline-block;
  margin: 0;
  padding: 2px 20px;
  background-color: rgb(245, 242, 240);
  border-top-left-radius: 5px;
  border-top-right-radius: 5px;
  border-bottom: 1px solid gray;
}