SwiftFormat/Sources/Rules/LinebreakAtEndOfFile.swift

//
//  LinebreakAtEndOfFile.swift
//  SwiftFormat
//
//  Created by Nick Lockwood on 8/22/16.
//  Copyright © 2024 Nick Lockwood. All rights reserved.
//

import Foundation

public extension FormatRule {
    /// Always end file with a linebreak, to avoid incompatibility with certain unix tools:
    /// http://stackoverflow.com/questions/2287967/why-is-it-recommended-to-have-empty-line-in-the-end-of-file
    static let linebreakAtEndOfFile = FormatRule(
        help: "Add empty blank line at end of file.",
        sharedOptions: ["linebreaks"]
    ) { formatter in
        guard !formatter.options.fragment else { return }
        var wasLinebreak = true
        formatter.forEachToken(onlyWhereEnabled: false) { _, token in
            switch token {
            case .linebreak:
                wasLinebreak = true
            case .space:
                break
            default:
                wasLinebreak = false
            }
        }
        if formatter.isEnabled, !wasLinebreak {
            formatter.insertLinebreak(at: formatter.tokens.count)
        }
    } examples: {
        """
        ```diff
          struct Foo {↩
              let bar: Bar↩
        - }
        + }↩
        +
        ```
        """
    }
}