What does the const modifier on a type parameter (TS 5.0) give you? function routes (r: T) { return r; } const r = routes(['home', 'about']);

Literal inference, like as const: r is readonly ['home', 'about']

A ban on modifying the argument inside the function at runtime

T can't be overridden by an explicit argument when calling

TypeScript · Senior · Question 11 of 75

What does the `const` modifier on a type parameter (TS 5.0) give you?

function routes<const T extends readonly string[]>(r: T) { return r; }
const r = routes(['home', 'about']);

✓Correct answer: Literal inference, like as const: r is readonly ['home', 'about']
2A ban on modifying the argument inside the function at runtime
3T can't be overridden by an explicit argument when calling

Explanation

Without const, string[] would be inferred, and the caller would have to write as const. The modifier affects only type inference, not runtime. The readonly string[] constraint is needed so an array literal fits as a readonly tuple.

What does the `const` modifier on a type parameter (TS 5.0) give you?

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