How to define a function in TypeScript

In TypeScript, you can define a function using the function keyword, similar to JavaScript. TypeScript provides static typing, allowing you to specify the types of parameters and the return type of a function. Here's a basic example:

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// Function without explicit types
function add(x, y) {
    return x + y;
}

// Function with explicit types
function addWithType(x: number, y: number): number {
    return x + y;
}

In the above example, the add function takes two parameters x and y without specifying their types, so TypeScript will infer them as any. The addWithType function, on the other hand, explicitly specifies that both parameters are of type number and that the function returns a value of type number.

You can also use arrow functions to define functions in TypeScript:

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// Arrow function without explicit types
const multiply = (x, y) => x * y;

// Arrow function with explicit types
const multiplyWithType = (x: number, y: number): number => x * y;

It's generally a good practice to provide explicit types for function parameters and return types to take advantage of TypeScript's static type checking and catch potential errors early in the development process.