# ★ guardFalse()

## `guardFalse()`

Guards the provided [`value`](#value-false) to be `false`.

{% code title="guard-false.func.ts" %}

```typescript
const guardFalse = <Payload extends object>(
  value: false,
  callback?: ResultCallback<false, Payload>,
  payload?: Payload
): value is false => isFalse(value, callback, payload);
```

{% endcode %}

{% embed url="<https://github.com/angular-package/type/blob/main/src/guard/lib/guard-false.func.ts>" %}

### Generic type variables

#### <mark style="color:green;">**`Payload`**</mark>**`extends`**<mark style="color:green;">**`object`**</mark>

The `Payload` generic type variable constrained by [`object`](https://www.typescriptlang.org/docs/handbook/basic-types.html#object) indicates the type of optional parameter [`payload`](https://type.angular-package.dev/type-draft/type/resultcallback#payload-payload) of the supplied [`callback`](#callback-resultcallback-less-than-false-payload-greater-than) function and [`payload`](#payload-payload) optional parameter of the [`guardFalse()`](#guardfalse) function from which it captures its value.

### Parameters

#### `value: false`

The value of `false` type to guard.

#### `callback?: ResultCallback<false, Payload>`

The optional callback [`function`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Functions) of [`ResultCallback`](https://type.angular-package.dev/type-draft/type/resultcallback) type with parameters, the `value` that has been checked, the [`result`](https://type.angular-package.dev/type-draft/type/resultcallback#result-boolean) of this check, and [`payload`](https://type.angular-package.dev/type-draft/type/resultcallback#payload-payload) of generic type variable [`Payload`](#payloadextendsobject) with optional properties from the provided [`payload`](#payload-payload), to handle them before the [`result`](https://type.angular-package.dev/type-draft/type/resultcallback#result-boolean) return. By default, it uses [`resultCallback()`](https://type.angular-package.dev/type-draft/helper/resultcallback) function.

#### `payload?: Payload`

An optional [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) of the generic type variable [`Payload`](#payloadextendsobject) is assigned to the [`payload`](https://type.angular-package.dev/type-draft/type/resultcallback#payload-payload) of the given [`callback`](#callback-resultcallback-less-than-false-payload-greater-than) function.

### Return type

#### `value is false`

The **return type** is a [`boolean`](https://www.typescriptlang.org/docs/handbook/basic-types.html#boolean) as the result of its statement [`value`](#value-false) is `false`.

### Returns

The **return value** is a [`boolean`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean) indicating whether the [`value`](#value-false) is a [`boolean`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean) type or an instance of [`Boolean`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean) equal to `false`.

## Example usage

```typescript
// Example usage.
import { guardFalse } from '@angular-package/type';

const valTrue = true as any;
const valFalse = false;

guardFalse(valTrue); // false, value is false
guardFalse(valFalse); // true, value is false
guardFalse(new Boolean(valTrue) as any); // false, value is false
guardFalse(new Boolean(valFalse) as any); // true, value is false
```