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Length<T>

EasyP2Coding

Implement Length<T>, the length of a tuple T as a number literal type. It must accept readonly tuples such as those produced by as const, and reject anything that is not an array type.

Tests your type must pass

const tesla = ['tesla', 'model 3', 'model X', 'model Y'] as const
const spaceX = ['FALCON 9', 'FALCON HEAVY', 'DRAGON', 'STARSHIP', 'HUMAN SPACEFLIGHT'] as const

type cases = [
  Expect<Equal<Length<typeof tesla>, 4>>,
  Expect<Equal<Length<typeof spaceX>, 5>>,
  Expect<Equal<Length<[]>, 0>>,
  Expect<Equal<Length<[1, 2]>, 2>>,
]

// @ts-expect-error a number is not an array
type error1 = Length<5>
// @ts-expect-error a string is not an array
type error2 = Length<'hello world'>

Hints

TypeScript
Run and Submit type-check your solution against the tests.