metalsmith@metalsmith/in-place
A metalsmith plugin for transforming source files' contents. Complements @metalsmith/layouts
Features
- renders source files'
contentsfield with any existing or a custom Jstransformer templating engine - alters file extensions from
transform.inputFormatstotransform.outputFormat - can be used multiple times with different configs per metalsmith pipeline
Installation
NPM:
npm install @metalsmith/in-place jstransformer-handlebars
Yarn:
yarn add @metalsmith/in-place jstransformer-handlebars
This plugin works with jstransformers but they should be installed separately. jstransformer-handlebars is just an example, you could use any transformer. To render markdown you could install jstransformer-marked. To render handlebars you would install jstransformer-handlebars. Other popular templating options include: Nunjucks, Twig, Pug, or EJS. See also this map to see which extensions map to which jstransformer.
Usage
Pass @metalsmith/in-place to metalsmith.use :
import inPlace from '@metalsmith/in-place'
// shorthand
metalsmith.use(inPlace({ transform: 'nunjucks' }))
// same as shorthand
metalsmith.use(
inPlace({
transform: jsTransformerNunjucks, // resolved
extname: '.html',
pattern: '**/*.{njk,nunjucks}*',
engineOptions: {}
})
)
In the transformed file, you have access to { ...metalsmith.metadata(), ...fileMetadata }, so that the following build
metalsmith.metadata({ title: 'Default title', nodeVersion: process.version }).use(inPlace({ transform: 'handlebars' }))
for a file:
---
title: Article title
---
<h1>{{ title }}</h1>Node v{{ nodeVersion }}
would render <h1>Article title</h1>Node v16.20
Multiple transforms can be used to target different sets of files, or to reprocess the same files multiple times in the order they are metalsmith.use'd:
// this build will apply the marked transform to index.md, the handlebars transform to index.hbs,
// and handlebars first, marked second to both index.hbs.md, index.md.hbs, and html-minifier to all (only in production)
metalsmith
.env('NODE_ENV', process.env.NODE_ENV)
.use(inPlace({ transform: 'handlebars', extname: null }))
.use(inPlace({ transform: 'marked' }))
if (metalsmith.env('NODE_ENV') !== 'development') {
metalsmith.use(inPlace({ transform: 'html-minifier' }))
}
Options
In most cases, you will only need to specify the transform and engineOptions option.
- transform (
string|JsTransformer): required. Which transformer to use. The full name of the transformer, e.g.jstransformer-handlebars, its shorthandhandlebars, a relative JS module path starting with., e.g../my-transformer.js, whose default export is a jstransformer or an actual jstransformer: an object withname,inputFormats,outputFormat, and at least one of the render methodsrender,renderAsync,compileorcompileAsyncdescribed in the jstransformer API docs - extname (
string|false|null): optional. How to transform a file's extensions:''|false|nullto remove the lasttransform.inputFormatmatching extension,.<ext>to force an extension rename. - engineOptions (
Object<string, any>): optional. Pass options to the jstransformer that's rendering the files. The default is{}. - pattern (
string|string[]): optional. Override default glob pattern matching**/*.<transform.inputFormats>*. Useful to limit the scope of the transform by path or glob to a subfolder, or to include files not matchingtransform.inputFormats.
Extension handling
By default in-place will apply smart default extension handling based on transform.inputFormats and transform.outputFormat.
For example, any of the source files below processed through inPlace({ transform: 'handlebars' }) will yield index.html.
| source | output |
|---|---|
| src/index.hbs | build/index.html |
| src/index.hbs.html | build/index.html |
| src/index.html.hbs | build/index.html |
The example demonstrates that:
- order of extensions doesn't matter, order of plugin execution does!: you can pick the final extension to match the most suitable editor syntax highlighting
- a single in-place run only alters the rightmost extension matching
transform.inputFormats - you may choose to include or omit the
transform.outputFormatin the source file name (.html in this case).
engineOptions
Pass options to the jstransformer that's rendering your templates via engineOptions. The
metalsmith.json:
{
"source": "src",
"destination": "build",
"plugins": [
{
"@metalsmith/in-place": {
"transform": "ejs",
"engineOptions": {
"cache": false
}
}
}
]
}
..would pass { "cache": false } to jstransformer-ejs.
If you use Pug, make sure to pass engineOptions: { filename: true }. This will ensure the filename of each processed file is passed to the render method as expected by this engine.
Multiple transforms per file
Suppose a file tags.hbs that lists all the article tags used on your website
---
title: Tags
description: Browse articles by tag
---
<h1>{{ title }}</h1>
<p>{{ description }}</p>
<ul>
{{#each tags}}
<li><a href="/tags/{{ . }}">{{ . }}</a></li>
{{/each}}
</ul>
To reduce Handlebars noise, you could add metalsmith.use(inPlace({ transform: 'marked' }) to your build and change the filename to tags.hbs.md to generate markdown syntax with Handlebars!
---
title: Tags
description: Browse articles by tag
---
# {{ title }}
{{ description }}
{{#each tags}}
- [{{.}}](/tags/{{ . }})
{{/each}}
More markdown here..
Caution: when using multiple templating transforms per file, make sure there is no conflicting syntax.
For example markdown will transform blocks indented by 4 spaces to <pre> tags, and marked's smartypants can potentially garble the result.
Usage with @metalsmith/layouts
In most cases @metalsmith/in-place is intended to be used before @metalsmith/layouts.
You can easily share engineOptions configs between both plugins:
import inPlace from '@metalsmith/in-place'
import layouts from '@metalsmith/layouts'
const engineOptions = {}
metalsmith // index.hbs.hbs
.use(inPlace({ transform: 'handlebars', extname: '', engineOptions })) // -> index.hbs
.use(layouts({ engineOptions })) // -> index.html
@metalsmith/layouts uses a similar mechanism targeting transform.inputFormats file extensions by default.
The example requires files ending in .hbs.hbs extension, but if you don't like this, you can just have a single .hbs extension, and change the in-place invocation to inPlace({ engineOptions, transform, extname: '.hbs' }) for the same result.
Debug
To enable debug logs, set the DEBUG environment variable to @metalsmith/in-place*:
metalsmith.env('DEBUG', '@metalsmith/in-place*')
Alternatively you can set DEBUG to @metalsmith/* to debug all Metalsmith core plugins.
Credits
- Ismay Wolff for improving upon metalsmith-templates & diligently maintaining its successor
- Ian Storm Taylor for creating metalsmith-templates, on which this plugin was based
- Rob Loach for creating metalsmith-jstransformer, which inspired our switch to jstransformers