Type Alias Immutable<T>

Immutable: T extends readonly [infer First, ...(infer Rest)]
    ? readonly [Immutable<First>, ...ImmutableTuple<Rest>]
    : T extends readonly (infer E)[]
        ? ReadonlyArray<Immutable<E>>
        : T extends Map<infer K, infer V>
            ? ReadonlyMap<Immutable<K>, Immutable<V>>
            : T extends Set<infer E>
                ? ReadonlySet<Immutable<E>>
                : T extends Record<string, infer V>
                    ? { readonly [P in keyof T]: Immutable<V> }
                    : T

Generic type that converts deeply nested structures into immutable variants.

Useful when you want to treat mutable shapes such as arrays, maps, sets, and plain objects as readonly data structures throughout your application.

Type Parameters

Example

import type { Immutable } from '@pacote/immutable'

type Foo = { foo: string }

const mutable: Foo[] = [{ foo: 'bar' }]

// Allowed:
mutable.push({ foo: 'baz' })
mutable[0].foo = 'baz'
delete mutable[0].foo

const immutable: Immutable<Foo[]> = [{ foo: 'bar' }]

// Not allowed:
immutable.push({ foo: 'baz' })
immutable[0].foo = 'baz'
delete immutable[0].foo

Type Alias Immutable<T>

Type Parameters

Example

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