index.js

const utils = require('loader-utils')

function performReplacement(source, options) {
  if (!options) return source

  const searchDefined = Boolean(options.search) || options.search === ''
  const replaceDefined = Boolean(options.replace) || options.replace === ''

  if (searchDefined && replaceDefined) {
    if (options.flags) {
      options.search = new RegExp(options.search, options.flags)
    }

    source = source.replace(options.search, options.replace)
  }

  return source
}

module.exports = function (source) {
  if (this.cacheable) {
    this.cacheable()
  }

  const optionsConfig = this.options || this.query
  const options =
    typeof optionsConfig === 'object' ? utils.getOptions(this) : utils.parseQuery(this.query)

  if (options && options.verbose) {
    console.log('\nReplacing in file:', this.resourcePath)
  }

  if (Array.isArray(options.multiple)) {
    options.multiple.forEach(function (opt) {
      source = performReplacement(source, opt)
    })
  } else {
    source = performReplacement(source, options)
  }

  return source
}