Type-only default+named imports

[robpalme]

Hegel and Flow support type-only imports of the default binding with named bindings like this:

// default import with named import
import type defaultBinding, { otherBinding } from "module"    // Error in TypeScript

The above is not supported by TypeScript: A type-only import can specify a default import or named bindings, but not both.

The workaround for TypeScript is to use an alias.

// default import with named import
import type { default as defaultBinding, otherBinding } from "module"

Should we widen the type-only import syntax to account for handling both immediate default imports and named imports?

[giltayar]

What am I missing? According to this, TS does support the Hegel/Flow syntax.

[ptomato]

I think it's the difference between

import type { APIResponseType } from "./api";

(import an exported type named APIResponseType) and

import type APIResponseType from "./api";

(import a default export type, and call it APIResponseType)

[robpalme]

Apologies I misled you first time around. Type-only default imports are supported in TypeScript. The only case that is not handled is requesting both the default and named bindings.

[giltayar]

Got it! And, yes, I say widen the support.

[robpalme]

I went back to the recent history on this. The reason the combined syntax was not added to TypeScript is because of a potential confusion.

import a, { type b } from 'mod'  // ONLY b is a type import - easily understood

vs

import type a, { b } from 'mod'  // BOTH a & b are type imports - is this obvious to all?

For the latter case, users might mistakenly think that { b } is a value import, assuming that type a binds tightly, when in fact the type applies to the entire statement.

I don't think this is essential to resolve right now. So I'd like to leave this as an open issue for now until we hear more from users.

[robpalme]

The champion group discussed this and concluded we will bring this into scope, meaning both default and named imports will be permitted in the same import declaration.

Note that this does not imply that TypeScript will permit the form. That's an independent decision.