ignores 'import ... =' in cjs output

[vdegenne]

• Rollup Version: 1.29.0
• Operating System (or Browser): Fedora 31/Chrome (last)
• Node Version: 13.6.0

How Do We Reproduce?

• install koa-bodyparser, @types/koa-bodyparser, rollup and typescript plugins
• then create the files
  input.ts

import bodyParser = require('koa-bodyparser');
console.log(bodyParser);

rollup.config.js

import typescript from '@rollup/plugin-typescript';

export default {
  input: 'input.ts',
  output: { file: 'output.js', format: 'cjs' },
  plugins: [typescript()]
}

• run rollup targeting cjs

Expected Behavior

output.js

'use strict';
const bodyParser = require('koa-bodyparser');
console.log(bodyParser);

output of vanilla typescript.

Actual Behavior

'use strict';
console.log(bodyParser);

generates an empty file.

[shellscape]

If you are sure this is a bug, please take the time to refile this issue using the issue template.

Hey there, thanks for opening an issue - Unfortunately you missed (or may have disregarded) the message about issue templates being required. Because our issue template was removed, we assume that this is a support request, and that's not something we offer here. Also, if you refile, please don't ignore Issue sections. They're in the template because they're useful to the maintainers of this project.

[vdegenne]

I reopen the issue and I changed my original post using the issue template because I think this is a bug.
(originated from : rollup/rollup#3341)

[lukastaegert]

Another thought from the Rollup issue:

• Typescript NEEDS to be configured to output CJS in order for this import style to be supported at all. Not sure if the plugin supports that
• Rollup NEEDS the CJS plugin in order to consume such output

My best guess is that the plugin tries to target ESM as this is the only format natively support by Rollup and at the same time does not emit the warning you get when doing that in the TS playground

I would assume that it works correctly if you just switch to either

import bodyParser from... or import * as bodyParser from..., no matter what the documentation of bodyParser says

[vdegenne]

Typescript NEEDS to be configured to output CJS in order for this import style to be supported at all. Not sure if the plugin supports that

You mean in the tsconfig.json ? I set module to commonjs already.

Rollup NEEDS the CJS plugin in order to consume such output

I also included the CJS plugin in the plugins array but still the import is not converted in the output.

I try everything possible before filing an issue and this particular one was bugging me to the point I had to open one, thought this could interest you because as a fallback and as you mentioned I can use the classic import ... from syntax so it's not like I don't have an immediate solution but again this is at least reported. Thanks again.

[NotWoods]

The plugin should work if the module type is set to commonjs and the commonjs plugin is included. We have an existing test for this behavior. I'll look into it and see if my other changes fix the issue.

[NotWoods]

@vdegenne Does configuring the plugin as typescript({ module: 'commonjs' }) fix the issue?

[vdegenne]

@NotWoods Sorry for the late reply.
I tried as you said, now it includes const bodyParser = require('koa-bodyparser') which is great but now all my default local imports are excluded from the build for instance

import myvar from './local/module'; // export default myvar = 'test';

is translated to

const myvar_1 = tslib_1.__importDefault(require("./local/module"));

I'd expect rollup to bundle that as well because they are local sources (not from the node_modules directory).

I tried to update to the last version of @rollup/plugin-typescript (3.0.0) but the problem persists, even worst if I just use typescript() it doesn't fallback to the previous output but instead the tslib importDefault function wrap all my local default import.

[shellscape]

@NotWoods housekeeping: think this is still relevant?