code splitting broken on Windows

[igisev]

What happens and why it is wrong

Briefly:
Code splitting is not supported now

Versions

• typescript: 3.5.3
• rollup: 1.20.3
• rollup-plugin-typescript2: 0.24.0

rollup.config.js

import resolve from 'rollup-plugin-node-resolve';
import ts2 from 'rollup-plugin-typescript2';

export default {
  // NOTE: object here
  input: {
    'my-lib': 'src/main.ts',
    'my-tools': 'src/tools.ts'
  },
  output: {
    dir: 'dist',
    format: 'esm'
  },
  plugins: [
    resolve(),
    ts2()
  ]
};

tsconfig.json

{
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "strict": true,
    "sourceMap": true,
    "importHelpers": true,
    "downlevelIteration": true,
    "moduleResolution": "node",
    "experimentalDecorators": true,
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,

    "lib": ["esnext"],
    "types": ["node"]
  },
  "include": ["src/**/*.ts"],
  "exclude": ["node_modules"]
}

files

src/tools.ts

export function myFn() {
    console.log('Hello World!');
}

src/main.ts

import { myFn } from './tools';

console.log(myFn());

plugin output

dist/my-tools.js OK

function myFn() {
    console.log('Hello World!');
}

export { myFn };

dist/my-lib.js WRONG

function myFn() {
    console.log('Hello World!');
}

console.log(myFn());

expected output

dist/my-lib.js

import { myFn } from './my-tools.js';

console.log(myFn());

[ezolenko]

Could you try the same thing with plain rollup, is it supposed to work? (turn ts into js manually and remove rpt2 from plugins)

[igisev]

Could you try the same thing with plain rollup, is it supposed to work?

This is a working well-tested feature in Rollup.
What is the point of checking it?
Rollup has a boilerplate: https://github.com/rollup/rollup-starter-code-splitting

Ok
case1:

• rollup-plugin-typescript2 is off
• all files renamed from ts to js

case2:

• no plugins at all
• all files renamed from ts to js

Result: output for case1 and case2 is identical (see below)

rollup.config.js

import resolve from 'rollup-plugin-node-resolve';

export default {
  // NOTE: object here
  input: {
    'my-lib': 'src/main.js',
    'my-tools': 'src/tools.js'
  },
  output: {
    dir: 'dist',
    format: 'esm'
  },
  plugins: [
    resolve()
  ]
};

output

dist/my-tools.js

function myFn() {
  console.log('Hello World!');
}

export { myFn };

dist/my-lib.js

import { myFn } from './my-tools.js';

console.log(myFn());

[ezolenko]

I see the problem, rollup doesn't normalize paths when using them as keys for code splitting. Workaround is to add rollupCommonJSResolveHack: true to rpt2 options (solves a similar problem with another plugin, they fixed it in recent release actually).

I'll open rollup bug.

[igisev]

It seems rollup is not going to fix.
@ezolenko, please. Can you solve this problem yourself?
This feature is critical for us.

[ezolenko]

@igisev can you use rollupCommonJSResolveHack: true as a workaround?