String union type lost when importing from json

[bali182]

When importing from a json file, some type information seems to be lost. Would it be worth to keep the strictest type information about the imported type? Eg.: in the example instead of inferring the { type: string } maybe infer { type: "frog" } instead?

TypeScript Version: 3.0.3

Search Terms:
json import string union type

Code

sample.json

{
  "type": "frog"
}

sample.ts

import sample from './sample.json'

type AnimalType = 'frog' | 'cat' | 'dog'
type Animal = { type: AnimalType }

const a: Animal = sample

Expected behavior:
No compliation error

Actual behavior:

Compile error: Type '{ "type": string; }' is not assignable to type 'Animal'.
Types of property 'type' are incompatible.
Type 'string' is not assignable to type 'AnimalType'.

[s-ve]

It's been discussed in #26552

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.