What are generics in TypeScript and why are they used? How do they differ from regular parameter typing?

Generics in TypeScript are a mechanism for parameterizing types, allowing the creation of components (functions, classes, interfaces) with universal types specified at use.

Regular parameter typing fixes a specific type, such as number or string. Generics, on the other hand, enable writing code that works with any type while preserving type information for validation and autocomplete.

For example, a function without generics:

function identity(arg: number): number {
  return arg;
}

It only works with numbers.

With generics:

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

Now, identity can accept and return a value of any type, and TypeScript knows that the input and output types match.

Why are generics needed:

• Reuse of code for different types.
• Preservation of type safety.
• Improved readability and maintainability of code.

Difference from regular parameter typing:

• Regular typing fixes a specific type.
• Generics allow parameterizing types, making the code universal and type-safe.

Thus, generics are a way to write generalized code that adapts to different types without losing type control.