module-from-string

module-from-string

Load module from string, require and import.

Install

npm install module-from-string

Usage

const { requireFromString, importFromString } = require('module-from-string')

requireFromString("module.exports = 'hi'") // => 'hi'
requireFromString("exports.greet = 'hi'") // => { greet: 'hi' }

;(async () => {
  await importFromString("export default 'hi'" ) // => { default: 'hi' }
  await importFromString("export const greet = 'hi'") // => { greet: 'hi' }
})()

API

import { TransformOptions } from 'esbuild'

interface Options {
  code: string
  globals?: Record<string, unknown>
}
declare const requireFromString: (options: string | Options) => any

interface ImportOptions extends Options {
  transformOptions?: TransformOptions
}
declare const importFromString: (
  options: string | ImportOptions
) => Promise<any>
declare const importFromStringSync: (options: string | ImportOptions) => any

export { importFromString, importFromStringSync, requireFromString }

globals

Underneath the hood, module-from-string uses Node.js built-in vm module to execute code.

const _module = new Module(String(new Date().valueOf()))

const context = vm.createContext({
  exports: _module.exports,
  module: _module,
  require,
  ...globals
})

vm.runInContext(code, context)

By default, only above variables are passed into the contextObject. In order to use other global objects you need to add them to option globals.

requireFromString('module.exports = process.cwd()', { process })

importFromStringSync({
  code: 'export default process.cwd()',
  globals: { process }
})

transformOptions

Function importFromString and importFromStringSync use esbuild to transform ES Module syntax to CommonJS. So it can do much more by providing transform options to esbuild. See esbuild Transform API for documentation.

const { greet } = importFromStringSync({
  code: "export const greet: () => string = () => 'hi'",
  transformOptions: { loader: 'ts' }
})

greet() // => 'hi'

License

MIT License © 2020 Exuanbo