Hands-On Functional Programming with TypeScript

Higher-order functions

A higher-order function is a function that does at least one of the following:

• Takes one or more functions as arguments
• Returns a function as its result

Higher-order functions are some of the most powerful tools that we can use to write JavaScript in a functional programming style. Let's look at some examples.

The following code snippet declares a function named addDelay. The function creates a new function that waits for a given number of milliseconds before printing a message in the console. The function is considered a higher-order function because it returns a function:

function addDelay(msg: string, ms: number) {    return () => {        setTimeout(() => {            console.log(msg);        }, ms);    };}const delayedSayHello = addDelay("Hello ...