Introduction to Generics

In TypeScript, generics are a way to create reusable functions that can work with multiple types.

Step 1: Define a Generic Function

Create a new file called utils.ts and add the following code:

function first<T>(arr: T[]): T {
  return arr[0];
}

This function returns the first element of an array of any type.

Step 2: Use the Generic Function

Add the following code to the utils.ts file:

console.log(first([1, 2, 3]));
console.log(first(['a', 'b', 'c']));

This code uses the first function with arrays of different types.

Step 3: Create a Generic Class

Add the following code to the utils.ts file:

class Container<T> {
  private value: T;
  constructor(value: T) {
    this.value = value;
  }
  getValue(): T {
    return this.value;
  }
}

This class is a generic container that can hold any type of value.