Invalid Typescript Types in lib/index.d.ts since 7.6.0

[adamdbradley]

Bug Report

Current Behavior
node_modules/@babel/types/lib/index.d.ts has invalid typescript since the 7.6.0 release: https://unpkg.com/browse/@babel/types@7.6.0/lib/index.d.ts line 2098

export function isNode(node: ?object): boolean

Environment

• Babel version(s): 7.6.0

Possible Solution
Move the ? before the :

[babel-bot]

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[matt-forster]

We can't move the ? unless you move the argument order, since the affected arguments are before others that are not optional.

[milesj]

@forstermatth Not sure what you mean. The ?<type> is invalid TS and is crashing any TS apps using Babel 7.6. This PR caused the issue: #10098

@tanhauhau

[matt-forster]

Yes - the possible solution offered in the issue report body would be incorrect. See my PR #10404

[trs]

@milesj It looks like the ?<type> syntax is a flow maybe type.
Changing these to a typescript optional type would fail in cases such as export function isPlaceholderType(placeholderType: ?string, targetType: string): boolean since non-optional types cannot follow an optional type.
If null or undefined are also explicitly allowed, then #10404 would be correct.

[starksds]

fyi, I reverted back to 7.5.5 and the error went away

[lancegliser]

Just for clarity. If you're going move back to 7.5.5, you should declare the @babel/types dependency directly. I had devDependencies for @babel/cli, @babel/core, @babel/preset-env, all pointing at 7.5.5. but they all allowed the upgraded version causing this issue.

[dantehemerson]

I have the same error using Nestjs

[cperryk]

For reference/searchability, the precise error on compiling is this: node_modules/@babel/types/lib/index.d.ts:2098:30 - error TS8020: JSDoc types can only be used inside documentation comments.

[nicolo-ribaudo]

Fixes in @babel/types 7.6.1. Thanks @forstermatth!