# assignToObject

**Kind:** Function

**Source:** [`packages/core/repl/assign-to-object.util.ts`](https://github.com/nestjs/nest/blob/master/packages/core/repl/assign-to-object.util.ts#L5)

**Part of:** [Core](subsystem-packages-core)

Similar to `Object.assign` but copying properties descriptors from `source`
as well.

`assignToObject` copies all own properties from a source object to a target object while preserving each property's descriptor, including getters, setters, enumerability, writability, and configurability. Unlike `Object.assign`, it does not read property values during copying, making it suitable for REPL and runtime utilities that need to retain object behavior accurately.

## Signature

```ts
function assignToObject(target: T, source: U): T & U
```

## Parameters

| Name | Type |
|---|---|
| `target` | `T` |
| `source` | `U` |

**Returns:** `T & U`

## Diagram

```mermaid
graph LR
  Source[Source object] --> Keys[Own property keys]
  Keys --> Descriptors[Get property descriptors]
  Descriptors --> Define[Define properties on target]
  Define --> Target[Target object]
```

## Usage

```ts
import { assignToObject } from './assign-to-object.util';

const source = {};

Object.defineProperty(source, 'computed', {
  enumerable: true,
  get() {
    return 'generated value';
  },
});

const target = { existing: true };

assignToObject(target, source);

console.log(target.existing); // true
console.log(target.computed); // "generated value"

const descriptor = Object.getOwnPropertyDescriptor(target, 'computed');
console.log(typeof descriptor?.get); // "function"
```

## AI Coding Instructions

- Use `assignToObject` when copied properties must retain getters, setters, and descriptor flags; use `Object.assign` only for plain value copying.
- Preserve own-property descriptor semantics, including symbol keys if the implementation supports them.
- Do not access source property values while copying, as doing so can invoke getters and change behavior.
- Ensure the target object can accept the copied descriptors; non-configurable target properties may cause `Object.defineProperty` to throw.
- Keep this utility focused on descriptor-preserving assignment for REPL object composition and runtime inspection flows.