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Alex Rupérez

Published: 15 Jul 13:09
I starred ethanhuang13/NSAttributedStringBuilder at GitHub.
Composing NSAttributedString with SwiftUI-style syntax
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Composing NSAttributedString with SwiftUI-style syntax, powerd by the now pitching Function Builder.

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🐦 Open source library written in Swift 5.1
🍬 SwiftUI-like syntax
💪 Support most attributes in NSAttributedString.Key
📦 Distribution with Swift Package Manager
🧪 Fully tested code
🛠 Continuously integrates in Swift Source Compatibility Suite

How to use?

Traditionally we compose a NSAttributedString like this:

let mas = NSMutableAttributedString(string: "")
mas.append(NSAttributedString(string: "Hello world", attributes: [.font: UIFont.systemFont(ofSize: 24), .foregroundColor:]))
mas.append(NSAttributedString(string: "\n"))
mas.append(NSAttributedString(string: "with Swift", attributes: [.font: UIFont.systemFont(ofSize: 20), .foregroundColor:]))

Now, with NSAttributedStringBuilder, we can use SwiftUI-like syntax to declare NSAttributedString:

let attributedString = NSAttributedString {
    AText("Hello world")
        .font(.systemFont(ofSize: 24))
    AText("with Swift")
        .font(.systemFont(ofSize: 20))


Xcode 11. This project uses Swift 5.1 feature Function Builder.


Swift Package

Open your project in Xcode 11, navigate to Menu -> Swift Packages -> Add Package Dependency and enter to install.


Add pod 'NSAttributedStringBuilder13' to your Podfile.

SwiftUI Sample Project

Besides clearer NSAttributedString syntax, since NSAttributedStringBuilder uses Function Builder it also enables API to build components in UIViewRepresentable(which embbed UIView in a SwiftUI View).

Just like a SwiftUI Text takes a String as input, the purpose of AttributedText in the sample project is to take a NSAttributedString as input and render in SwiftUI.

To achieve this, AttributedText.swift uses @NSAttributedStringBuilder to support SwiftUI-style syntax:


Then using an AttributedText will be like: ContentView.swift

Open the sample in /SwiftUISampleApp/AttributedTextSample.xcodeproj and check AttributedText. It uses UITextView, you can also use UILabel or NSTextView.


  • Better tests for image attachment

Known Issue

  • NSAttributedString does not support link color, therefore Link component with a .color() modifier has no effect. Alternatively you need to specify in UITextView.linkTextAttributes or .tintColor.


Initially discussed on this Twitter thread. Some code are inspired by zonble🙏.