Parse string to rich text

richtextparse.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

@immutable
class MyHomePage extends StatelessWidget {
  final String title;

  const MyHomePage({
    Key? key,
    required this.title,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: const [
            RandomTextWithIcon("any random string with a 🐔 inside"),
            RandomTextWithIcon("any random string ending with a 🎁"),
            RandomTextWithIcon("any random string without smiles 🏳️‍🌈"),
          ],
        ),
      ),
    );
  }
}

@immutable
class RandomTextWithIcon extends StatelessWidget {
  final String text;
  
  const RandomTextWithIcon(this.text);
  
  InlineSpan _byPlaceholder(String text) {
    switch(text) {
      case '🐔': return const WidgetSpan(child: Icon(Icons.add));
      case '🎁': return const WidgetSpan(child: Icon(Icons.power));
      default: return TextSpan(text: text);
    }
  }
  
  @override
  Widget build(BuildContext context) {
    return Text.rich(TextSpan(
        children: text
            .split(' ')
            .map(_byPlaceholder)
            .expand((a) => [a, const TextSpan(text: ' ')])
            .toList()));
  }
}