Extensions

How do we use extensions?

We use extensions to break up our code into logical groups, e.g. when separating code specifically for protocol conformance into its own extension.

Key Considerations

• Declare protocol conformance to a type as an extension in the same file as that type declaration, if possible.
• Declare an extension that will only be used in a single file, in the same file that will use it, e.g. an Array extension constrained to a specific type of element used elsewhere in that file.
• Declare general-purpose extensions for other frameworks in their own files.
  • Name the file in the format <Extended type>+<Word or phrase about the extension>, e.g. Array+MergeSort.swift.

Example

extension UITableView {
    
    /// Hides the empty cells at the bottom of the table view.
    func hideEmptyCellsFooter() {
        tableFooterView = UIView()
    }
}