[Basic] Import React "allowSyntheticDefaultImports" no longer valid

[rpivo]

What cheatsheet is this about? (if applicable)

Basic cheatsheet

What's your issue or idea?

I think the paragraph in the doc about --allowSyntheticDefaultImportsvs esModuleInterop is no longer true. See the answers to this Stack Overflow question: https://stackoverflow.com/questions/52576203/do-i-ever-need-explicit-allowsyntheticdefaultimports-if-esmoduleinterop-is-true. Also see this now closed issue in the TypeScript GitHub discussing this: microsoft/TypeScript#26193.

[swyxio]

thanks for the heads up! however i think in this case i dont think your sources are as accurate as mine is... (which is dan rosenwasser) - make sure to read his tweet. i don't see any of these comments being aware of this nuance.

[rpivo]

Yeah, I almost decided to go with --allowSyntheticDefaultImports, but that Stack Overflow thread also linked to this TypeScript Github issue from August 2018, a little after the tweet from June 2018: microsoft/TypeScript#26193

In that thread, Daniel Rosenwasser and another TypeScript contributor discuss this, and it seems like the merged PR that came from the issue makes --allowSyntheticDefaultImports true whenever esModuleInterop is true.

It's also mentioned in the Compiler Options documentation under the esModuleInterop description: https://www.typescriptlang.org/docs/handbook/compiler-options.html

Emit __importStar and __importDefault helpers for runtime babel ecosystem compatibility and enable --allowSyntheticDefaultImports for typesystem compatibility.

(honestly, I need further clarification on these two -- just wondering how they work after the above mentioned PR, and based on what the docs say)

[orta]

I wrote fresh docs for them both here BTW: https://www.typescriptlang.org/v2/en/tsconfig#allowSyntheticDefaultImports

[rpivo]

Thanks -- that cleared it up for me a lot.