Unexpected token when importing *.d.cts or *.d.mts files from helmet

[phun-ky]

I'm trying to bundle helmet with rollup-plugin-typescript2, but I keep getting this error, is it related directly to helmet or is this a ts/rpt2 issue?

[!] (plugin rpt2) RollupError: Unexpected token (Note that you need plugins to import files that are not JavaScript)
../../node_modules/helmet/index.d.cts (3:5)
1: import {IncomingMessage, ServerResponse} from "http"
2: 
3: type ContentSecurityPolicyDirectiveValueFunction = (req: IncomingMessage, res: ServerResponse) => string
        ^
4: type ContentSecurityPolicyDirectiveValue = string | ContentSecurityPolicyDirectiveValueFunction
5: interface ContentSecurityPolicyOptions {

    at error (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:279:30)
    at Module.error (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:13947:16)
    at Module.tryParse (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:14658:25)
    at Module.setSource (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:14260:39)
    at ModuleLoader.addModuleSource (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:24225:20)

[!] (plugin rpt2) RollupError: Unexpected token (Note that you need plugins to import files that are not JavaScript)
../../node_modules/helmet/index.d.mts (3:5)
1: import {IncomingMessage, ServerResponse} from "http"
2: 
3: type ContentSecurityPolicyDirectiveValueFunction = (req: IncomingMessage, res: ServerResponse) => string
        ^
4: type ContentSecurityPolicyDirectiveValue = string | ContentSecurityPolicyDirectiveValueFunction
5: interface ContentSecurityPolicyOptions {

    at error (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:279:30)
    at Module.error (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:13947:16)
    at Module.tryParse (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:14668:25)
    at Module.setSource (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:14270:39)
    at ModuleLoader.addModuleSource (/home/alexander/Workspace/company/internal/devplatform-server-api/node_modules/rollup/dist/shared/rollup.js:24266:20)

The original issue is here: ezolenko/rollup-plugin-typescript2#446

[EvanHahn]

I'm not sure, but I assume this is an issue with the Rollup plugin. Helmet's type definitions look correct to me, and seem to be working well for others.

I'm going to close this issue, but let me know if that's wrong and I can reopen.