Hack to extract a String from SwiftUI.Text

Text+String.swift

// Cursed! Do not use!

// Supports most, but not all Text initializers.

import SwiftUI

extension FormatStyle {
    func format(any value: Any) -> FormatOutput? {
        if let v = value as? FormatInput {
            return format(v)
        }
        return nil
    }
}

extension LocalizedStringKey {
    var resolved: String? {
        let mirror = Mirror(reflecting: self)
        guard let key = mirror.descendant("key") as? String else {
            return nil
        }

        guard let args = mirror.descendant("arguments") as? [Any] else {
            return nil
        }

        let values = args.map { arg -> Any? in
            let mirror = Mirror(reflecting: arg)
            if let value = mirror.descendant("storage", "value", ".0") {
                return value
            }

            guard let format = mirror.descendant("storage", "formatStyleValue", "format") as? any FormatStyle,
                  let input = mirror.descendant("storage", "formatStyleValue", "input") else {
                return nil
            }

            return format.format(any: input)
        }

        let va = values.compactMap { arg -> CVarArg? in
            switch arg {
            case let i as Int:      return i
            case let i as Int64:    return i
            case let i as Int8:     return i
            case let i as Int16:    return i
            case let i as Int32:    return i
            case let u as UInt:     return u
            case let u as UInt64:   return u
            case let u as UInt8:    return u
            case let u as UInt16:   return u
            case let u as UInt32:   return u
            case let f as Float:    return f
            case let f as CGFloat:  return f
            case let d as Double:   return d
            case let o as NSObject: return o
            default:                return nil
            }
        }

        if va.count != values.count {
            return nil
        }

        return String.localizedStringWithFormat(key, va)
    }
}

extension Text {
    var string: String? {
        let mirror = Mirror(reflecting: self)
        if let s = mirror.descendant("storage", "verbatim") as? String {
            return s
        } else if let attrStr = mirror.descendant("storage", "anyTextStorage", "str") as? AttributedString {
            return String(attrStr.characters)
        } else if let key = mirror.descendant("storage", "anyTextStorage", "key") as? LocalizedStringKey {
            return key.resolved
        } else if let format = mirror.descendant("storage", "anyTextStorage", "storage", "format") as? any FormatStyle,
                  let input = mirror.descendant("storage", "anyTextStorage", "storage", "input") {
            return format.format(any: input) as? String
        } else if let formatter = mirror.descendant("storage", "anyTextStorage", "formatter") as? Formatter,
                  let object = mirror.descendant("storage", "anyTextStorage", "object") {
            return formatter.string(for: object)
        }
        return nil
    }
}

Text("Hello world!").string                   // => "Hello world!"
Text(AttributedString("Hello world!")).string // => "Hello world!"
Text("Hello \("world")!").string              // => "Hello world!"
Text("Hello \(1 + 2)").string                 // => "Hello 3
Text("Hello \(Date())").string                // => "Hello Friday, January 19, 2024 at 11:25:59 Eastern Standard Time"
Text("Hello \(0.8, format: .percent)").string // => "Hello 80%"
Text(0.8, format: .percent).string            // => "80%"

let formatter = DateFormatter()
formatter.dateStyle = .medium
formatter.timeStyle = .none

Text(Date(), formatter: formatter).string   // => "Jan 19, 2024"
Text(NSDate(), formatter: formatter).string // => "Jan 19, 2024"