Merge pull request #2194 from woocommerce/update/docs-coding-guidelines

Docs: Add Coding Guidelines about Structs vs Classes

Author: shiki

docs/README.md

@@ -1,12 +1,26 @@
 # WooCommerce for iOS 
 
-## Getting Started
-
-- [Coding Style Guide](coding-style-guide.md)
-
 ## Architecture
 
 - [Architecture](ARCHITECTURE.md)
 - [Networking](NETWORKING.md)
 - [Storage](STORAGE.md)
 - [Yosemite](YOSEMITE.md)
+
+## Coding Guidelines
+
+### Coding Style
+
+The guidelines for how Swift should be written and formatted can be found in the [Coding Style Guide](coding-style-guide.md).
+
+### Choosing Between Structures and Classes
+
+In addition to the [Apple guidelines](https://developer.apple.com/documentation/swift/choosing_between_structures_and_classes), we generally prefer to use `struct` for: 
+
+- Value types like the [Networking Models](../../../Networking/Networking/Model)
+- Stateless helpers 
+
+But consider using `class` instead if:
+
+- You need to manage mutable states. Especially if there are more than a few `mutating` functions, the `struct` becomes harder to reason about.
+- You have to set a `struct` property declaration as `var` because it has a `mutating` function. In this case, a constant (`let`) `class` property may be easier to reason about.