Description
Bug Report
Type narrowing using the typeof operator seems to act differently if an early parenthesis grouping is used.
🔎 Search Terms
type narrowing typeof parentheses
🕗 Version & Regression Information
4.1.3
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about type narrowing
⏯ Playground Link
Playground link with relevant code
💻 Code
declare const foo: string
if (typeof foo === 'string') {
console.log(foo)
} else {
// @ts-expect-error
console.log(foo.toString()) // errors, 'foo' is type 'never'
}
if ((typeof foo) === 'string') {
console.log(foo)
} else {
// @ts-expect-error
console.log(foo.toString()) // doesn't error, 'foo' is still type 'string'
}🙁 Actual behavior
In the second case, foo isn't narrowed to type never.
🙂 Expected behavior
In the second case, foo is narrowed to type never.