ReadonlyArray<T>
Represents an array of T whose elements cannot be modified.
Syntax
ReadonlyArray<Type>Returns
array type — An immutable array view exposing only non-mutating members.
Examples
const nums: ReadonlyArray<number> = [1, 2, 3];
// nums.push(4); // Error: push does not exist
const doubled = nums.map(n => n * 2);
function sum(values: readonly number[]): number {
return values.reduce((a, b) => a + b, 0);
}
Notes
Equivalent to the shorthand `readonly T[]`. Mutating methods like `push`,
`pop`, and index assignment are removed at the type level. A regular array is
assignable to a `ReadonlyArray`, but not the reverse.