Function isLength

isLength<T, N extends number>(
arr: readonly T[],
length: N,
): arr is TupleOf<T, N>
Checks whether an array has an exact length, narrowing the type to a fixed-length tuple.
Type Parameters
- T
- N extends number
Parameters
- arr: readonly T[]
  Array whose length is compared.
- length: N
  Exact length to match; when equal, narrows arr to a fixed-length tuple type.
Returns arr is TupleOf<T, N>
true when arr.length equals length exactly.
Example
```
const values: number[] = [1, 2, 3];
if (isLength(values, 3)) {
  // values: [number, number, number]
}
isLength(values, 2); // false
```
- Defined in array.ts:44