Warning when importing module with rollup

[CameronNemo]

(!) `this` has been rewritten to `undefined`
https://rollupjs.org/guide/en/#error-this-is-undefined
node_modules/graphql-ws/lib/server.mjs
4:  *
5:  */
6: var __asyncValues = (this && this.__asyncValues) || function (o) {
                        ^
7:     if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
8:     var m = o[Symbol.asyncIterator], i;
...and 1 other occurrence

Expected Behaviour

Import and bundle module without warnings with rollup.

Actual Behaviour

Saw the above warning.

Other

https://rollupjs.org/troubleshooting/#error-this-is-undefined

[enisdenjo]

Hey there, the bundled code you're referencing comes from the TypeScript compiler. The only option we have here is to use the importHelpers: true option for TSC; however, this would introduce an additional dependency of tslib and increase the bundle size completely unnecessarily - this is something I don't intent to do.

The warning is actually safe to ignore, but if you insist on removing it - you should use the context: "this" option with rollup.

Read more:

• An Option to stop - 'rewrite THIS to UNDEFINED'  rollup/rollup#3788
• Noisy warning from Rollup: The 'this' keyword is equivalent to 'undefined' developit/microbundle#682