Multiple document capable webpack loader, ES6 syntax, js-yaml

webpack-yaml-multidoc-loader.js

/*

yaml loader
+ safeLoad for one doc
+ safeLoadAll for multiple docs

questions:
+ does it need yaml parser `onWarning: this.emitWarning`?
+ does it need error handling e.g. `try-catch`?

*/

import yaml from 'js-yaml'

// look for lines starting with new doc
let openingDocPattern = /^---/g

function yamlLoader(source) {
  let op
  
  // assume single doc
  let loadFn = yaml.safeLoad

  this.cacheable()

  // is this a multi-doc yaml?
  if (openingDocPattern.test(source)) {
    // yes
    loadFn = yaml.safeLoadAll
  }

  // parse
  op = loadFn(source.toString(), {
    filename: this.resourcePath,
    json: true
  })

  // turn into js module text
  op = JSON.stringify(op)
  op = 'module.exports = ' + op

  return op
}

export default yamlLoader