Chapter 1

1. Using union types, we can write a method that accepts either the FahrenheitToCelsius class or the CelsiusToFahrenheit class:

class Converter {
    Convert(temperature : number, converter : FahrenheitToCelsius | CelsiusToFahrenheit) : number {
        return converter.Convert(temperature);
    }
}

let converter = new Converter();
console.log(converter.Convert(32, new CelsiusToFahrenheit()));

2. To accept a key/value pair, we need to use a map. Adding our records to it would look something like this:

class Commands {
    private commands = new Map<string, Command>();
    public Add(...commands : Command[]) {
        commands.forEach(command => {
            this.Add(command);
        })
    }
    public Add(command : Command) {
        this.commands.set(command.Name, command);
    }
}

let command = new Commands();
command.Add(new Command("Command1", new Function()),...