Docs: Confusion about when allowSyntheticDefaultImports is true

[joebowbeer]

Page URL:

https://www.typescriptlang.org/docs/handbook/compiler-options.html

https://github.com/microsoft/TypeScript-Website/edit/v2/packages/documentation/copy/en/project-config/Compiler%20Options.md

Issue:

The documentation is confusing regarding when allowSyntheticDefaultImports is true.

The esModuleInterop documentation says enabling it will also enable allowSyntheticDefaultImports. However on this page, the allowSyntheticDefaultImports documentation says that it will be:

true if module is system, or esModuleInterop and module is not es6/es2015 or esnext, false otherwise.

It is not clear for example, what happens by default if esModuleInterop is true and module is es2019.

Recommended Fix:

TBD

[sapphi-red]

It seems the allowSyntheticDefaultImports documentation should be "true if module is system, or esModuleInterop, false otherwise".

v4.7.4: https://github.com/microsoft/TypeScript/blob/76401adba33b71e70d76961d7d66064243be0243/src/compiler/utilities.ts#L6432-L6438
v4.4.4: https://github.com/microsoft/TypeScript/blob/01de6ff2ecdc6175727f7f999b887519d40ca115/src/compiler/utilities.ts#L6121-L6127