babelPluginGenerateLanguageKatalog.js

// THIS IS JUST A POC. DO NOT USE THIS CODE!

module.exports = function babelPluginGenerateLanguageKatalog(api, options) {
  const componentNames = ['FormattedMessage']
  const functionNames = ['formatMessage']

  const foundIds = new Set()

  return {
    inherits: require('babel-plugin-syntax-jsx'),
    visitor: {
      Program: {
        exit(path, state) {
          // TODO: Process aggregated language keys.
          // Maybe by generating a manifest?
          console.log(state.file.opts.filename, Array.from(foundIds))
        },
      },
      JSXOpeningElement(path) {
        const name = path.get('name')

        if (!componentNames.find((n) => name.isJSXIdentifier({ name: n }))) {
          return
        }

        const idAttr = path.node.attributes.find(
          (attr) => attr.name.name === 'id'
        )

        foundIds.add(idAttr.value.value)
      },
      CallExpression(path) {
        const callee = path.get('callee')

        if (!isFormatMessageCall(callee, functionNames)) {
          return
        }

        const [messageDescriptor] = path.get('arguments')
        if (messageDescriptor.isObjectExpression()) {
          const properties = messageDescriptor.get('properties')

          const idProp = properties.find((prop) => {
            const keyProp = prop.get('key')
            return (
              keyProp.isIdentifier({ name: 'id' }) ||
              keyProp.isStringLiteral({ value: 'id' })
            )
          })

          foundIds.add(idProp.node.value.value)
        }
      },
    },
  }
}

function isFormatMessageCall(callee, functionNames) {
  if (functionNames.find((name) => callee.isIdentifier({ name }))) {
    return true
  }

  if (callee.isMemberExpression()) {
    const property = callee.get('property')
    return !!functionNames.find((name) => property.isIdentifier({ name }))
  }

  return false
}