TypeScript: Replacement character (`\uFFFD`) in JavaScript/TypeScript causes to breaks

🔎 Search Terms

• TS1490: File appears to be binary
• replacement character

🕗 Version & Regression Information

#57008 is incorrect on some real files.

⏯ Playground Link

https://github.com/micromark/micromark/pull/166

💻 Code

Note the � in the first 256 characters.

import assert from 'node:assert/strict'
import test from 'node:test'
import {micromark} from 'micromark'

test('nul', function () {
  assert.equal(
    micromark('asd\0asd'),
    '<p>asd�asd</p>',
    'should replace `\\0` w/ a replacement characters (`�`)'
  )
})

🙁 Actual behavior

error TS1490: File appears to be binary

🙂 Expected behavior

0xFFFD should be fine among other regular characters.

Additional information about the issue

Related-to: #21136. Related-to: #56516. Related-to: #57008.