es-toolkit/docs/reference/function/once.md

# once

Creates a function that is restricted to invoking the provided function `func` once.
Repeated calls to the function will return the value from the first invocation.

## Signature

```typescript
function once<F extends () => any>(func: F): F;
```

### Parameters

- `func` (`F extends () => any`): The function to restrict.

### Returns

(`F`): A new function that invokes `func` once and caches the result.

## Examples

```typescript
const initialize = once(() => {
  console.log('Initialized!');
  return true;
});

initialize(); // Logs: 'Initialized!' and returns true
initialize(); // Returns true without logging
```