Readonly

readonly is a function to create a ReadonlyGrain, which is the basic form of a Grain. A ReadonlyGrain can be subscribed to, but cannot be updated by it self.

Type: readonly<V>(grain: Grain<V>): ReadonlyGrain<V>

Creating a ReadonlyGrain

A ReadonlyGrain is returned by the derived, combined & get methods. You can also use the standalone readonly function to create a ReadonlyGrain:

import { grain, readonly } from '@grainular/nord';

const _count = grain(0);
const count = readonly(_count); // Returns a `ReadonlyGrain<number>`

TIP

Use a ReadonlyGrain if you want to prevent updates to the grain in any form.

The created ReadonlyGrain will receive an update anytime the source Grain is updated.

Accessing a ReadonlyGrain's value

A ReadonlyGrain's value can be accessed just like a normal Grain's value. You can call it as a function or subscribe to it. To learn more about Subscribers and Subscriptions, take a look a the corresponding section of the grain page.

import { grain, readonly } from '@grainular/nord';

const _count = grain(0);
const count = readonly(_count); // Returns a `ReadonlyGrain<number>`
console.log(count()); // logs 0;

// Subscribe to the readonly grain
const unsubscriber = count.subscribe((value) => console.log({ value }));
unsubscribe();

In The Code:

You can see the function signature & implementation here: readonly.ts

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Code insights: You can see the function signature & implementation here: readonly.ts