Usage of T in Typescript
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.