SwiftUI: is there exist modifier to highlight substring of Text() view?

Question

I have some text on the screen:

Text(\"someText1\")

is it possible to highlight/select part of the text without creating lot Text items

Answer 1

Disclaimer: I was really reluctant to post my answer since I am sure that there must be a lot of way-smarter, way-better (I dunno maybe a wrapper to a UIKit view using TextKit) and more robust approaches, but... what the heck I thought it was a fun exercise and maybe someone could actually benefit from it.

So here we go:

Instead of a modifier, I'm going to make a view that holds a string (to render) and another one to hold our 'matching' text.

struct HighlightedText: View {
    let text: String
    let matching: String

    init(_ text: String, matching: String) {
        self.text = text
        self.matching = matching
    }

    var body: some View {
        let tagged = text.replacingOccurrences(of: self.matching, with: ">\(self.matching)")
        let split = tagged.components(separatedBy: "")
        return split.reduce(Text("")) { (a, b) -> Text in
            guard !b.hasPrefix(">") else {
                return a + Text(b.dropFirst()).foregroundColor(.red)
            }
            return a + Text(b)
        }
    }
}

I guess the code is quite self-explanatory but in a nutshell:

1. Find all matches
2. Replace them by hardcoded 'tags' (marking the beginning of a match by another hardcoded character)
3. Split on the tags
4. Reduce the components & return a stylized version if we're on a match

Now, we can use it with something like this:

struct ContentView: View {
    @State var matching: String = "ll"
    var body: some View {
        VStack {
            TextField("Matching term", text: self.$matching)
            HighlightedText("Hello to all in this hall", matching: self.matching)
            .font(.largeTitle)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

Here is a (crappy) gif demonstrating it in action:

https://imgur.com/sDpr0Ul

Finally, in case you're wondering how I'm running SwiftUI outside Xcode, here is a gist I've made for prototyping quickly in SwiftUI on the Mac