gongzhxu/babel-plugin-content-transformer

babel-plugin-content-transformer

Easily transform YAML, TOML, and Markdown into normal JavaScript objects and convert directories of content into arrays at build time.

Install

npm i -D babel-plugin-content-transformer

Usage

Transform a directory of Markdown files into an array of strings

['content-transformer', 
  transformers: [
    // Convert import statements ending with ".md" into strings
    {
      file: /\.md$/,
      format: 'string'
    }
  ],
  content: [
    // Import statements ending with "content" are converted into
    // an array of imports. The array will only include ".md" files
    {
      dir: /content$/,
      filter: /\.md$/
    }
  ]
}]

Load YAML files as objects

Requires yaml to be installed.

// Matches ".yaml" and ".yml" imports and converts them to JS objects
['content-transformer', {
  transformers: [{
    file: /\.ya?ml$/,
    format: 'yaml'
  }]
}]

Load TOML files as objects

Requires toml to be installed.

['content-transformer', {
  transformers: [{
    file: /\.toml/,
    format: 'toml'
  }]
}]

Custom transformation

This custom transformer will extract frontmatter from Markdown files and transform it into an object with the Markdown content in a "body" property.

// babel.config.js
const parse = require('remark-parse')
const stringify = require('remark-stringify')
const frontmatter = require('remark-frontmatter')
const extract = require('remark-extract-frontmatter')
const yaml = require('yaml')

module.exports = {
  plugins: [
    ['content-transformer', {
      transformers: [{
        file: /\.md$/,
        transform (contents, filename) {
          const file = unified()
            .use(parse)
            .use(stringify)
            .use(frontmatter)
            .use(extract, { yaml: yaml.parse })
            .processSync(contents)
          const data = { ...file.data }
          if (file.toString()) {
            data.body = file.toString()
          }
          return data
        }
      }]
    }]
  ]
}

Configuration

Transformers

All transformers need to have at minimum a "file" definition. This indicates which files should be transformed. Either a "transform" or "format" block can be provided, but not both. If both are omitted, the file is loaded as a string.

Name	Type	Description	Required	Default
file	RegExp	Which files to transform. An object with a "test" method like a RegExp.	true
transform	(contents: string, filename: string) => any	A custom transformation function.	false
format	string	One of 'yaml', 'toml', 'string'	false	'string'

Content

Content blocks transform directories into arrays for easy consumption. Can be used together with transformers for easy content loading.

Name	Type	Description	Required	Default
dir	RegExp	Indicates which import statements should be treated as content directories.	true
filter	RegExp	Filters out files within matching directories	false	null