Type Alias IsReadonly<A, $Options>

IsReadonly: TypePlusOptions.Merge<$Options, ArrayPlus.IsReadonly.DefaultOptions> extends infer O extends
    ArrayPlus.IsReadonly.Options
    ? IsNever<
        A,
        {
            $else: A extends any
                ? LooseArrayType<
                    A,
                    Readonly<A> extends A ? O["$then"] : O["$else"],
                    O["$notArray"],
                >
                : never;
            $then: O["$never"];
        },
    >
    : never

🎭 predicate 🔢 customizable

Checks if A is a readonly array or tuple

Type Parameters

A
$Options extends ArrayPlus.IsReadonly.Options = ArrayPlus.IsReadonly.DefaultOptions

Example

type R = IsReadonly<readonly string[]> // true
type R = IsReadonly<readonly [1, 2, 3, 4, 5]> // true

type R = IsReadonly<[1, 2, 3, 4, 5]> // false
type R = IsReadonly<readonly string[] | number> // boolean

Type Alias IsReadonly<A, $Options>

Type Parameters

Example

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