rollup-plugin-typescript2: `TS2354 This syntax requires an imported helper but module 'tslib' cannot be found.`

I see that the code has some references to tslib and importHelpers so I assume this should work transparently. If not, I’ll be happy to know what is missing.

Here is how to reproduce:

Installed packages:

$ npm ls --depth=0
├── resolve@1.3.2
├── rollup@0.41.6
├── rollup-plugin-typescript2@0.4.0
├── tslib@1.6.0
└── typescript@2.2.2

tsconfig.json:

{
    "compilerOptions": {
        "target": "es5"
    }
}

rollup.config.js:

import typescript from 'rollup-plugin-typescript2';

export default {
	entry: './main.ts',

	plugins: [
		typescript()
	]
}

main.ts:

import {Foo} from './module';

console.log("HERE" + Foo);

And module.ts:

export class Foo {}

export class Bar extends Foo {}

When running rollup as follows:

./node_modules/.bin/rollup -c rollup.config.js

I get this error:

🚨   rpt2: module.ts (3,18): semantic error TS2354 This syntax requires an imported helper but module 'tslib' cannot be found.
module.ts

I think this is because the extends syntax requires an __extends helper from tslib, but typescript can’t find tslib.

Expected result is that the required helpers become part of the bundle.

Thanks.

About this issue

Original URL
State: closed
Created 7 years ago
Reactions: 5
Comments: 19 (6 by maintainers)

Commits related to this issue

fix: weird tslib error on object spread operator https://github.com/ezolenko/rollup-plugin-typescript2/issues/12 — committed to jasonkuhrt/forto by jasonkuhrt 6 years ago
build: fix package-lock https://github.com/ezolenko/rollup-plugin-typescript2/issues/12#issuecomment-537133693 — committed to victorhqc/touchbar-electron-renderer by victorhqc 5 years ago
chore: upgrade rollup-plugin-typescript2(v0.30.0), add tslib - to fix module 'tslib' cannot be found error - ref: https://github.com/ezolenko/rollup-plugin-typescript2/issues/12 — committed to greatSumini/react-analytics-provider by greatSumini 3 years ago
chore: Yarn berry 설정 (#163) * chore: add .yarnrc.yml * chore: add yarn-berry.cjs * chore: install packages with yarn berry * chore: ignore yarn related files * chore: remove package-lock.... — committed to EveryAnalytics/react-analytics-provider by greatSumini 3 years ago
added tslib dev lib because of this issue https://github.com/ezolenko/rollup-plugin-typescript2/issues/12\#issuecomment-536173372 — committed to apperside/react-query-typed-api by apperside 2 years ago

Most upvoted comments

Looks like you need "moduleResolution": "node" in tsconfig, otherwise typescript can’t find tslib in node_modules.

Not sure if that could pose problems on non-node setups, but I haven’t heard anything to that effect yet.

+89

ezolenko on Jun 21, 2022

@hueitan i faced the same issue while already having "moduleResolution": "node". Fixed it by adding "tslib": "^1.10.0" to my devDependencies.

+87

giniedp on Sep 28, 2019

This was fixed with this

@hueitan i faced the same issue while already having "moduleResolution": "node". Fixed it by adding "tslib": "^1.10.0" to my devDependencies.

Fixed! Mine was in regular dependencies.

+35

imnickvaughn on Jun 21, 2022

Not sure anyone else facing the same problem as mine.

I was having this problem https://github.com/rollup/rollup-plugin-typescript/issues/109, therefore I switch to this repo, but then I’m getting this tslib error.

as the tsconfig is already "moduleResolution": "node"

+26

hueitan on Sep 19, 2019

in my case i am using yarn. Deleting the yarn.lock and reinstalling fresh, i do not need an explicit mention of tslib in the package.json

I can reproduce it in the following repo:

https://github.com/giniedp/tweak-ui

git clone git@github.com:giniedp/tweak-ui.git
cd tweak-ui
git checkout v0.1.0

now edit the package.json and remove tslib. Then do

yarn install
yarn run build

you should run into

This syntax requires an imported helper named '__spreadArrays', but module 'tslib' has no exported member '__spreadArrays'

now delete the yarn.lock and then

yarn install
yarn run build

runs fine.

+17

giniedp on Oct 1, 2019

Fixed it by adding "tslib": "^1.10.0" to my dependencies.

vishnu-85 on Jun 21, 2022

npm i tslib -D

worked for me too

Seanmclem on Jun 21, 2022

adding tslib as the dependencies work to me as well. although not the pretty solution

hueitan on Oct 1, 2019

None of the proposed solutions worked for me. Upgrading rollup-plugin-typescript2 did the trick.

npm i rollup-plugin-typescript2@0.27.1

It turns out rollup was using tslib@1.9.3 even when I had ^1.10.0 in devDependencies. I realized rollup-plugin-typescript2 was overriding the tslib version. I was using v0.20.1; upgraded to v0.27.1.

caroso1222 on Jul 7, 2020

Like @ezolenko says: While npm i tslib -D works, this should not be used as the solution, because:

tslib is already a dependency of rollup-plugin-typescript2, how does it end up missing on your system?

Do you use npm install or something else?

What worked in my case and is the better solution is to delete package-lock and node_modules and reinstall.

rm -rf ./node_modules
rm -rf ./package-lock.json
npm i

mesqueeb on Feb 26, 2021

You can simply upgrade your tslib version. I did mine from tslib@2.0.0 to tslib@^2.2.0 which is the latest one by the time and it fixed my "__spreadArray" issue.

aman2talk on Jun 21, 2022

tslib is already a dependency of rollup-plugin-typescript2, how does it end up missing on your system?

Do you use npm install or something else?

ezolenko on Oct 1, 2019

If you post your tsconfig, rollup config and package.json, somebody might spot something amiss.

ezolenko on Sep 19, 2019

Indeed, with "moduleResolution": "node", it works as expected. Reading https://www.typescriptlang.org/docs/handbook/module-resolution.html, I think "node" is a better fit for me, so I’ll just use it. May I suggest mentioning/recommending it in the README?

I see that you opened #14 for the "classic" case, so I’ll close this. Thanks!

bluetech on Apr 19, 2017