Usage of T in Typescript

Sanjana Human In Tech
1 min readNov 12, 2023

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Generic types

In TypeScript, T is often used as a type variable or a placeholder for a type. TypeScript is a statically typed superset of JavaScript that adds static typing to the language.

When you see T in TypeScript code, it typically represents a generic type parameter. Generics allow you to write functions and classes that work with various types while providing type safety.

Here’s a simple example of using T as a generic type parameter in a function:

function genericType<T>(arg: T): T {
return arg;
}

let result = identity<string>("Hello, TypeScript!");
console.log(result); // Output: Hello, TypeScript!

In this example, T is a placeholder for the type of argument passed to the identity function. The function returns the same type it receives.

You can also use T in the context of interfaces and classes when defining generic types. For instance:

interface Box<T> {
value: T;
}

let box: Box<number> = { value: 42 };
console.log(box.value); // Output: 42

Here, Box<T> is an interface that represents a box holding a value of type T. The variable box is declared to be of type Box<number>, indicating that it holds a numeric value.

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Sanjana Human In Tech
Sanjana Human In Tech

Written by Sanjana Human In Tech

A React Native front-end enthusiast and dedicated development engineer, eager to expand knowledge on development techniques and collaborate with others.

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