Everything You Need To Know To Master Typing Functions in TypeScript
The ultimate guide to mastering the art of typing functions in TypeScript, equipped with all the necessary tools and knowledge to ensure your success.
Published in
5 min readMar 19, 2023
Too many function syntaxes are available, even when writing JavaScript. Sometimes this can be very confusing. So how can we type these functions with TypeScript?
Today we will study this topic. Let’s get started.
1. Function Declarations
2. Function Expressions
3. Optional and Default Parameters
4. Rest Parameters
5. Methods for Object properties
6. Methods for Classes
7. Async Functions
Function Declarations
function addNumbers(x: number, y: number): number {
return x + y
}
Function Expressions
Named Function Expression
let addNumbers = function addNumbers(x: number, y: number): number {
return x + y
}
Anonymous Function Expression
let addNumbers = function (x: number, y: number): number {
return x + y
}
Using explicit return for arrow functions
let addNumbers = (x: number…