mongodb - Does typescript automatically bundle all exports as default?

Question

import * as mongodbModule from 'mongodb';

The above code is the standard es6 way to import mongodb in nodejs, doing it like so import mongodbModule from 'mongodb' is supposed to throw an error because the mongodb module has no default export; but it still works. I discovered that the mongodb module is a typescript file hence my question.

question from:https://stackoverflow.com/questions/65927073/does-typescript-automatically-bundle-all-exports-as-default

Answer 1

Whether or not you can write import mongodbModule from 'mongodb' without getting an error depends on your configuration in .tsconfig. In order to enable this, you use the setting --allowSyntheticDefaultImports. As explained in the docs, it's not really that typescript creates the bundle, it's more that typescript assumes that the bundle exists and allows you to import it, while babel handles the actual creation of it.

This flag does not affect the JavaScript emitted by TypeScript, it only for the type checking. This option brings the behavior of TypeScript in-line with Babel, where extra code is emitted to make using a default export of a module more ergonomic. ... For convenience, transpilers like Babel will automatically create a default if one isn’t created.