> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/arrays-and-objects/cloning-and-references.md).

# Clone Objects And References

## Basic Concepts

OSL provides two ways to assign arrays and objects:

* `=` creates a reference (points to the same data)
* `.clone()` creates a deep clone (complete copy)

## References with `=`

When using `=`, OSL creates a reference to the original object or array (both variables point to the same data):

```javascript
// Objects
original = {x: 1, y: {z: 2}}
reference = original     // Creates a reference

reference.x = 10        // Affects both objects
reference.y.z = 20      // Affects both objects

log original.x          // Now 10
log original.y.z        // Now 20

// Arrays
arr1 = [1, 2, [3, 4]]
arr2 = arr1             // Creates a reference

arr2[1] = 10            // Affects both arrays
arr2[3][1] = 40         // Affects both arrays

log arr1[1]             // Now 10
log arr1[3][1]          // Now 40
```

## Deep Cloning with `.clone()`

Use the `.clone()` method to create an independent copy of the object or array:

```javascript
// Objects
original = {x: 1, y: {z: 2}}
clone = original.clone()    // Creates a deep copy

clone.x = 10                // Only affects clone
clone.y.z = 20              // Only affects clone

log original.x              // Still 1
log original.y.z            // Still 2

// Arrays
arr1 = [1, 2, [3, 4]]
arr2 = arr1.clone()         // Creates a deep copy

arr2[1] = 10                // Only affects arr2
arr2[3][1] = 40             // Only affects arr2

log arr1[1]                 // Still 1
log arr1[3][1]              // Still 4
```

## When to Use Each

* Use `=` when you want multiple variables to point to the same data
* Use `.clone()` when you need a separate copy that can be modified independently
* Use `.clone()` to prevent accidental modifications to the original
* Use `=` to save memory when working with large data structures (all modifications are shared)

## Important Notes

* `=` creates a reference; both variables point to the same data
* `.clone()` creates a complete copy of all nested structures
* Modifying a reference affects all variables pointing to the same data
* References are useful for passing large objects efficiently
* Deep clones are safer but use more memory