Convert your external module to String and catches the module body to inject using executeJavaScript on Electron

prepare-module-for-injection.js

const prepareModuleForInjection = code => {
  const moduleBody = /(?<=\{return\s).*(?=})|(?<=({(?![return]))).*(?=})|(?<=\=>\s)(?=[a-z]).*|(?<=\=>)\n.*/gsi
  const [extractedBody] = String(code).match(moduleBody) || ''

  return extractedBody
    ? `${extractedBody.trim()}\n\n`
    : ''
}

webview.executeJavaScript(
  prepareModuleForInjection(yourModule)
)