Creating a Swift Package

At it's core, the entire Edge developer experience is built around Swift and Swift Packages.

Developer Requirements

• It's recommended that you develop on a macOS or Linux Machine. If you have a Windows machine, you can use the Windows Subsystem for Linux (WSL) to develop on a Linux machine.
• We highly recommend only targeting Swift 6.1 and above.

Make sure you have swift installed.

Creating a Swift Package

To create a Swift Package, you can use the swift package init command. This will create a new Swift Package in the current directory.

# Create a new directory for the package
mkdir MyCoolLibrary
# Navigate to the directory
cd MyCoolLibrary
# Initialize the package
swift package init --type library --name MyCoolLibrary

This will create a new Swift Package in the current directory. The --type library flag will create a library package.

With your favorite text editor; (we recommend VSCode, Cursor, or Windsurf) open the directory with:

# if you have VSCode installed
code .
# if you have Cursor installed
cursor .
# if you have Windsurf installed
windsurf .

Then begin coding.

• All of your swift source code should be in the Sources directory.
• All of your tests should be in the Tests directory.
• If you have any resources such as images, files, or other assets, you can put them in the Resources directory and make sure to add them to the Package.swift file like so:

let package = Package(
    name: "MyCoolLibrary",
    resources: [.process("Resources")]
)

Source Code

Add all of your source code to the Sources directory like so:

public func add(_ a: Int, _ b: Int) -> Int {  
    return a + b
}

Testing

You'll always want to write unit tests for your code. We highly recommend only using Swift Testing for your tests instead of XCTest.

Add all of your tests to the Tests directory like so:

@testable import MyCoolLibrary

@Test("Addition of two numbers", arguments: [
    (1, 2),
    (2, 3),
    (3, 4),
    (4, 5),
])
func additionOfTwoNumbers(a: Int, b: Int) async throws {
    let result = try await MyCoolLibrary.add(a, b)
    #expect(result == a + b)
}

swift test

Building

To build your package, you can use the swift build command. This will build your package and output the binary to the ./build directory.

Releasing a package

1. We recommend publishing your package to GitHub where the current directory is the root of the package.
2. Then make a new release on GitHub. If you have the gh CLI installed, you can use the gh release create command to create a new release with:

gh release create v1.0.0

Tips

We recommend taking a look at our CBOR library as inspiration for your own package. You could clone it, and modify it to be a good starting point for your own package.

Using Your Package from GitHub

Once you've published your package to GitHub, other developers can easily use it in their projects. In the downstream project's Package.swift file, add your package as a dependency:

// swift-tools-version: 6.0
import PackageDescription

let package = Package(
    name: "MyApp",
    dependencies: [
        // Add your package from GitHub
        .package(url: "https://github.com/yourusername/MyCoolLibrary.git", from: "1.0.0")
    ],
    targets: [
        .target(
            name: "MyApp",
            dependencies: [
                // Add the package to your target dependencies
                .product(name: "MyCoolLibrary", package: "MyCoolLibrary")
            ]
        )
    ]
)

You can specify the version in different ways:

• from: "1.0.0" - Use version 1.0.0 or any newer version
• exact: "1.0.0" - Use exactly version 1.0.0
• .upToNextMajor(from: "1.0.0") - Use any version from 1.0.0 up to (but not including) 2.0.0
• branch: "main" - Use a specific branch
• revision: "abc123..." - Use a specific commit

Using Your Package Locally

During development, you might want to use a local version of your package. This is useful when you're developing both the package and the app that uses it simultaneously. You can specify a local path in your Package.swift:

// swift-tools-version: 6.0
import PackageDescription

let package = Package(
    name: "MyApp",
    dependencies: [
        // Add your package from a local path
        .package(path: "../MyCoolLibrary")
    ],
    targets: [
        .target(
            name: "MyApp",
            dependencies: [
                // Add the package to your target dependencies
                .product(name: "MyCoolLibrary", package: "MyCoolLibrary")
            ]
        )
    ]
)