Dynamically change or reassign object types in TypeScript

Check out the example you can copy and test in TypeScript Playground:

class GreetMessage {
message: {};
constructor(msg: string) {
    let newTyping: { textMsg: string }; // reassign necessary
    this.message = newTyping;
    this.message.textMsg = msg; // typing issue
}
getMessage() {
    return "Greetings, " + this.message.textMsg;
 }
}

let greetMsg = new GreetMessage("universe");

let btn = document.createElement('button');
btn.textContent = "Show Greeting";
btn.onclick = function() {
    alert(greetMsg.getMessage());
}

document.body.appendChild(btn);

In the code snippet above, there is an error with this.message.textMsg which requires reassigning {} to {textMsg: string} type.

Is it possible to achieve dynamic reassignment since I am uncertain about the type that will be used to populate the object during runtime (thus default typing) ?

Your assistance on this matter would be greatly appreciated. Thank you!

Answer №1

In TypeScript, there exists a distinct type known as any specifically designed for such scenarios. It serves as a better representation of a "default type" compared to an empty object type ({}). When the compiler lacks any type information for a symbol (e.g., variable or property), it automatically defaults to using the any type.

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