ffc-pay-etl-framework/app/transformers/faker-transformer.js

A framework for creating ETL pipelines in node

const { Transform } = require('node:stream')

/**
 *
 * @param {Object} options
 * @param {Array} options.columns {
 *           columns: [
 *               {
 *                   name: "column-name",
 *                   faker: "company.name"
 *               }
 *           ]
 *       }
 * @param {String} options.locale
 * @returns StreamReader
 */
function fakerTransformer (options) {
  const columns = options.columns
  let faker
  if (options.locale) {
    faker = require(`@faker-js/faker/locale/${options.locale}`).faker
  } else {
    faker = require('@faker-js/faker').faker
  }

  function getFaker (fakerType) {
    return fakerType.split('.').reduce((a, b) => {
      return Object.keys(a).length === 0 ? faker[b] : a[b]
    }, {})
  }

  return new Transform({
    readableObjectMode: true,
    writableObjectMode: true,
    transform (chunk, _, callback) {
      const { _columns } = chunk
      columns.forEach(column => {
        const colIndex = _columns.indexOf(column.name)
        chunk[colIndex] = getFaker(column.faker)()
      })
      callback(null, chunk)
    }
  })
}

module.exports = {
  FakerTransformer: fakerTransformer
}