# isObjectKeysIn()

## `isObjectKeysIn()`

Checks if [`any`](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#any) value is an [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)(by using the [`isObject()`](/type/is/isobject.md)) with [`keys`](#keys-propertykey) of the `PropertyKey` in it(or its prototype chain) by using the [`in`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/in) operator.

{% code title="is-object-keys-in.func.ts" %}

```typescript
const isObjectKeysIn = <Obj = object, Payload extends object = object>(
  value: any,
  keys: PropertyKey[],
  callback: ResultCallback<
    any,
    { keys: typeof keys } & Payload
  > = resultCallback,
  payload?: Payload
): value is Obj =>
  callback(
    isObject(value) && isArray(keys) ? keys.every((k) => k in value) : false,
    value,
    { ...payload, keys } as any
  );
```

{% endcode %}

### Generic type variables

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

A generic type variable `Obj` indicates the type of the given [`value`](#value-any) parameter via the [return type](#return-type) `value is Obj`, by default [`object`](https://www.typescriptlang.org/docs/handbook/basic-types.html#object).

#### <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`](/type/type/resultcallback.md#payload-payload) of the supplied [`callback`](#callback-resultcallback-less-than-any-keys-typeof-keys-and-payload-greater-than) function and [`payload`](#payload-payload) optional parameter of the [`isObjectKeysIn()`](#isobjectkeysin) function from which it captures its value.

### Parameters

#### `value: any`

The value of [`any`](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#any) type to check against the [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) that contains(or its prototype chain) keys from the given [`keys`](#keys-propertykey).

#### `keys: PropertyKey[]`

An [`Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array) of property keys to check if a given [`value`](#value-any) contains(or its prototype chain).

#### `callback: ResultCallback<any, { keys: typeof keys } & Payload>`

A callback `function` of [`ResultCallback`](/type/type/resultcallback.md) type with parameters, the [`value`](#value-any) that has been checked, the [`result`](/type/type/resultcallback.md#result-boolean) of this check, and [`payload`](/type/type/resultcallback.md#payload-payload) of generic type variable [`Payload`](#payloadextendsobject-object) with optional properties from the provided [`payload`](#payload-payload), to handle them before the [`result`](/type/type/resultcallback.md#result-boolean) return. By default, it uses [`resultCallback()`](/type/helper/resultcallback.md) function.

{% hint style="info" %}
The [`payload`](/type/type/resultcallback.md#payload-payload) parameter of the [`callback`](#callback-resultcallback-less-than-any-keys-typeof-keys-and-payload-greater-than) function consists of the [`keys`](#keys-propertykey) property given in parameter of the core function, and it can't be overwritten by the given [`payload`](#payload-payload) parameter of the core function.
{% endhint %}

#### `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`](/type/type/resultcallback.md#payload-payload) of the given [`callback`](#callback-resultcallback-less-than-any-keys-typeof-keys-and-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-any) is a generic type variable [`Obj`](#obj-object) by default equal to the [`object`](https://www.typescriptlang.org/docs/handbook/basic-types.html#object).

### 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-any) is an [`object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) that contains(or its prototype chain) given [`keys`](#keys-propertykey).

## Example usage

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

class Person {
  firstName = 'name';
  surname = 'surname';
  age = 27;
  city = 'New York';
  sex = 'Male';
  get getAge(): number {
    return this.age;
  }
}
const person = new Person();
// Define property.
Object.defineProperty(person, 'notEnumerable', { enumerable: false });
person.propertyIsEnumerable('notEnumerable'); // Returns `false`.
isObjectKeysIn(person, ['firstName']); // Returns `true` as `value is object`.
isObjectKeysIn(person, ['firstName', 'surname']); // Returns `true` as `value is object`.
isObjectKeysIn(person, ['firstName', 'no property']); // Returns `false` as `value is object`.
// Getter.
isObjectKeysIn(person, ['getAge']); // Returns `true` as `value is object`.
// not enumerable.
isObjectKeysIn(person, ['notEnumerable']); // Returns `true` as `value is object`.
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.angular-package.dev/type/is/isobjectkeysin.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.