handlebarsPartials.js

// We specify partials with an arrow and expect to simply find them
// because out old build would register them manually in a rewrite.
// We should be able to find them by referencing them relative to the jst directory

function addPartialLeader (fullName) {
  const refPieces = fullName.split('/')
  refPieces[refPieces.length - 1] = `_${refPieces[refPieces.length - 1]}`
  return refPieces.join('/')
}

module.exports = function (input) {
  this.cacheable()
  const partialsRegexp = /\{\{>(.+)( |})/g
  // search for all things that look like partial references {{>partial}},
  // replace them with {{> $jst/_partial}}
  let newInput = input.replace(partialsRegexp, partialInvocation => {
    const fixedInvocation = partialInvocation.replace(/([^\{\}> ]+) ?/, partialName => {
      // replace the name of the partial with a reference webpack can resolve
      const newPartialName = addPartialLeader(`$jst/${partialName}.handlebars`)
      return newPartialName
    })
    return fixedInvocation
  })

  // search for all sub-partial references like {{>[assignments/partial],
  // replace them with {{> $jst/assignments/_partial}}
  const subPartialsRegexp = /\{\{> ?\[.+?\]/g
  newInput = newInput.replace(subPartialsRegexp, partialInvocation => {
    const absoluteReferencedPartial = partialInvocation.replace('[', ' $jst/').replace(']', '')
    const fixedInvocation = addPartialLeader(absoluteReferencedPartial)
    return fixedInvocation
  })

  return newInput
}