Provide API method to transform a source code string

[mtsknn]

The currently provided transform method takes a path to a file (or an array of paths) and optionally writes the transformed file(s) to the file system.

It would be nice to provide another method which takes a source code string and returns a transformed source code string. For example:

import {transform} from 'cjstoesm'

const input = `
  const {foo: bar} = require("./my-module")
  module.exports = {baz: 3}
`

await transform({ input })
//=> 'import {foo as bar} from "./my-module.js"\nexport const baz = 3'

(The method name could be different.)

[caoxiemeihao]

It's very useful！ 👏👏👏👏

[caoxiemeihao]

Maybe you can use it like this

import { transpileModule, ModuleKind } from 'typescript'
import { cjsToEsm } from 'cjstoesm'

const input = `
  const {foo: bar} = require("./my-module")
  module.exports = {baz: 3}
`

const result = transpileModule(input, {
  transformers: cjsToEsm(),
  compilerOptions: {
    module: ModuleKind.ES2020,
  },
})

// console.log(result.outputText)

[ghh-l-djl]

I have the same needs

[satouriko]

I have the same needs

[satouriko]

We can use https://github.com/streamich/memfs as a filesystem to read from memory