Ambient types not working for json import assertions with moduleResolution: Node16/NodeNext

[dnalborczyk]

Bug Report

🔎 Search Terms

json import assertions ambient types

⏯ Playground Link

n/a

💻 Code

locationData.json.d.ts

export interface Location {
  id: string
}

declare const locations: Location[]

export default locations

locationData.json

[
  {
    "id": "loc-1"
  }
]

index.ts

import locations from './locationsData.json' assert { type: 'json' }
import type { Location } from './locationsData.json'

tsconfig.json

{
  "compilerOptions": {
    "esModuleInterop": true,
    "module": "ESNext",
    "moduleResolution": "NodeNext",
    "outDir": "dist",
    "strict": true,
    "target": "ESNext",
  },
}

🙁 Actual behavior

locations is untyped (any)

🙂 Expected behavior

locations should be typed

it works as expected with "moduleResolution": "Node"

[fatcerberus]

Does this even work at all? I thought this required #50133

[weswigham]

Yep, this never worked - your declaration file is actually for locationsData.json.js, which is commonjs often looks close enough, but in the case of native esm, won't cut it. You need #50133.