What is type narrowing in programming languages?

What is type narrowing in programming languages?

Type narrowing is a technique used in programming to refine the type of a variable based on certain conditions, allowing for more specific operations.

Can you give me an example of type narrowing in TypeScript?

Sure! In TypeScript, you can use the typeof operator to narrow down a variable's type. For example:

function example(value: string | number) {
    if (typeof value === 'string') {
        console.log(value.toUpperCase()); // value is narrowed to string
    } else {
        console.log(value.toFixed(2)); // value is narrowed to number
    }
}

Is type narrowing available in other languages like Java or Python?

Yes, type narrowing concepts exist in other languages too. In Java, you can use instanceof to check an object's type, while in Python, type hints and runtime checks can help achieve similar narrowing.

What are the benefits of using type narrowing?

The benefits include improved type safety, better code readability, and enhanced autocompletion features in IDEs, which can lead to fewer runtime errors.