microsoft/TypeScript

Dynamic import compiles to `require()`, which throw errors when importing ES modules

aquapi opened this issue · 5 comments

aquapi commented

Bug Report

The dynamic import feature supports importing ES modules into CommonJS modules. npx tsc compiles dynamic import to __importStar(require()) which cannot import ES modules

💻 Code

import("file.mjs")

🙁 Actual behavior

__importStar(require("file.mjs"))

🙂 Expected behavior

import("file.mjs")
RyanCavanaugh commented

To get that behavior, set module to esnext

  • 👎5
typescript-bot commented

This issue has been marked as 'Question' and has seen no recent activity. It has been automatically closed for house-keeping purposes. If you're still waiting on a response, questions are usually better suited to stackoverflow or the TypeScript Discord community.

magicdawn commented

Hello here is the use case.

we want TypeScript emit commonjs modules in node.js, and node tell us we can use
dynamic import in commonjs module to load an esm module. https://nodejs.org/dist/latest-v16.x/docs/api/esm.html#import-expressions

tsconfig.compilerOptions.module can not be changed, since esm & commonjs have many differneces, migrate a whole project would be a big effort.

  • 👍2
magicdawn commented

same as #43329

sguillia commented

To get that behavior, set moduleResolution to node16 while leaving module to commonjs.

This will convert all imports to requires, except dynamic imports (await import())

  • 👍9