# guardObject()

## `guardObject()`

Guards the value to be an [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) of a generic type variable [`Obj`](#objextendsobject). The function guards only generic objects, not **specific** objects.

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

```typescript
const guardObject = <
  Obj extends object,
  Payload extends object = object
>(
  value: Obj,
  callback?: ResultCallback<Obj, Payload>,
  payload?: Payload
): value is Obj => isObject(value, callback, payload);
```

{% endcode %}

Code on [**GitHub**](https://github.com/angular-package/type/blob/5.0.x/src/guard/lib/guard-object.func.ts).

### Generic type variables

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

A generic type variable `Obj` constrained by [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) indicates captured [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) type of the given [`value`](#value-obj) via the [return type](#return-type) and the [`value`](https://docs.angular-package.dev/type/type/resultcallback#value-value) parameter of the provided [`callback`](#callback-resultcallback-less-than-type-payload-greater-than) function [`ResultCallback`](https://docs.angular-package.dev/type/type/resultcallback) type.

#### <mark style="color:green;">**`Payload`**</mark>**`extends`**<mark style="color:green;">**`object`**</mark>**`=`**<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://docs.angular-package.dev/type/type/resultcallback#payload-payload) of the supplied [`callback`](#callback-resultcallback-less-than-type-payload-greater-than) function and [`payload`](#payload-payload) optional parameter of the [`guardObject()`](#guardobject) function from which it captures its value.

### Parameters

#### `value: Obj`

An [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) of a generic type variable [`Obj`](#objextendsobject), by default of the type captured from itself to guard.

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

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

### Return type

#### `value is Obj`

The **return type** is a [`boolean`](https://www.typescriptlang.org/docs/handbook/basic-types.html#boolean) as the result of its statement indicating the [`value`](#value-obj) is an [`object`](https://www.typescriptlang.org/docs/handbook/basic-types.html#object) of a generic type variable [`Obj`](#objextendsobject), by default of type captured from the supplied [`value`](#value-obj).

### Returns

The **return value** is a [`boolean`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean) indicating whether the provided [`value`](#value-obj) is an [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)[ ](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)of a generic type variable [`Obj`](#objextendsobject).

## Example usage

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

class Person {}
const o = {};
const p = new Person();

guardObject(o); // true, value is {}
guardObject(p); // true, value is Person
```