> For the complete documentation index, see [llms.txt](https://ss3d.gitbook.io/dev-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ss3d.gitbook.io/dev-guide/guidelines/the-c-style-guide/declarations/common-patterns-and-structure.md).
# Common Patterns and Structure
This section includes some rules of thumb for design patterns and code structure
#### Error handling
**Avoid** throwing **exceptions**. Instead **log** and **error**. **Methods** returning **values** should **return null** in addition to **logging** an **error**
**BAD:**
```
public List FindAThing(int arg){
...
if (notFound) {
throw new NotFoundException();
}
}
```
**GOOD:**
```
public List FindAThing(int arg){
...
if (notFound) {
Debug.LogError("Thing not found");
return null;
}
}
```
#### Finding references
Don't use **Find** or in other ways refer to **GameObjects** by **name** or **child index** *when possible*. **Reference by reference** is less error prone and more flexible. Expect people to set the **fields** in the inspector and log warnings if they don't.
**BAD:**
```
private GameObject _someMember;
private void Start() {
_someMember = GameObject.Find("ObjectName");
}
```
#### RequireComponent
Prefer **RequireComponent** and **GetComponent** over **AddComponent**. Having the **components** in the inspector let's us edit them. **AddComponent** limits us.
**BAD:**
```
public class : MonoBehaviour
{
private AudioSource _audioSource;
private void Start() {
_audioSource = gameObject.AddCompenent();
}
}
```
**GOOD:**
```
[RequireComponent(typeof(AudioSource))]
public class : MonoBehaviour
{
private AudioSource _audioSource;
private void Start() {
_audioSource = GetCompenent();
}
}
```
#### Properties with backing fields
**Properties** can be used for access control to **fields**, and when using **backing fields** they can be **private** and let us change them in the inspector. Consider when a **fields** should be **public** and prefer **properties with backing fields**.
Sometimes it's just nice to see them for debugging, even if we don't change them, so consider making more of your private fields visible.
**OKAY:**
```
public GameObject SomeMember;
```
**BETTER:**
```
[SerializeField] private GameObject _someMember;
public GameObject SomeMember => _someMember;
```
---
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