JSFiddle - React, Tailwind, and code Playground

by gorillawit

JavaScript

/* set i to a function that accepts a number as a value 
and returns the sum of num + 1 */
let i = num => num + 1;

let j = i(2);

/* alterNum gets passed two values, an array (num) and a function (fn) */
let alterNum = (nums, fn) => {
	/* create a new emplty array to hold the new values */
	let newNums = [];
	/* iterate over each item in the array and push the value of the result
	of fn(num) which is addOne(num) */
	for (let num of nums) {
		newNums.push(fn(num));
	}
	/* return new array */
	return newNums;
}

/* set addOne to a function that accepts a value (num) and returns the sum or num + 1 */
let addOne = num =>  num + 1;

/* call alterNum and pass in two parameters, an array and a function call */
alert(alterNum([1,2,3], addOne));  // 2,3,4