external files are being bundled for commonjs

[dnalborczyk]

Rollup Version

2.60.0

Operating System (or Browser)

n/a

Node Version (if applicable)

n/a

Link To Reproduction

n/a

Expected Behaviour

.

Actual Behaviour

foo.js

const foo = require("./foo.js")

console.log(foo)

foo.js

module.exports = "foo";

rollup.config.js

import commonjs from "@rollup/plugin-commonjs";

export default {
  external: ["./foo.js"],
  input: "./index.js",
  output: {
    file: "./build/bundle.js",
    format: "module",
  },
  plugins: [commonjs()],
}

bundled:

import './foo.js';

var requireTest = {};

var require$$0 = "foo";

const foo = require$$0;

console.log(foo);

export { requireTest as default };

possibly a commonjs-plugin bug (also does not work with the json plugin). might ignore the external setting, or rollup is not passing it along. hence I'm filing it here.

works when source files are esm.

import foo from "./foo.js"

console.log(foo)

export default "foo"

bundled:

import foo from './foo.js';

console.log(foo);

failed attempt to cross file: rollup/plugins#1044

[FoxDaxian]

it is works after remove commonjs:

export default {
  external: ["foo.js"],
  input: "./index.js",
  output: {
    exports: 'auto',
    file: "./build/bundle.js",
    format: "cjs",
  },
  plugins: [],
}

output:

'use strict';

const foo = require("./foo.js");

console.log(foo);

seem need file issue to rollup/plugins again.

[FoxDaxian]

actually rollup provides some use case in rollup/test/form/samples/external-imports/main.js

[dnalborczyk]

it is works after remove commonjs:

thanks @FoxDaxian , you are right. now I'm entirely lost and confused. 🤔

seem need file issue to rollup/plugins again.

not going to. out of principle.

[lukastaegert]

This is indeed an issue with the commonjs plugin. I added a fix to the PR rollup/plugins#1038 I am working on at the moment. May take a while until it is merged though (by the way, that one will look for more beta testers soon).

[dnalborczyk]

@FoxDaxian

it got a little late yesterday. I was surprised as I thought he commonjs syntax is unknown to rollup. and as it turns out, it is. this is not really working without the commonjs plugin, as you get to the same result excluding the external parameter. bundling is effectively being ignored for this part of the commonjs code.

export default {
  // external: ["foo.js"], <--- removed
  input: "./index.js",
  output: {
    exports: 'auto',
    file: "./build/bundle.js",
    format: "cjs",
  },
  plugins: [],
}

[FoxDaxian]

@dnalborczyk
I think it is.
and used import after remove external. will output as below:

'use strict';
var foo = "foo";
console.log(foo);

rollup do not have require statement node, it can deal with import statement only. so it result like external even though excluding the external.

---

can not found some require statement node

[FoxDaxian]

maybe this can explain the problem we encountered: