arrow_func.js

//Non-arrow function expression:
// const square = function (x) {
//   return x * x;
// }

// Equivalent arrow function:
const square = (x) => {
	return x * x;
};

//parens are option when you have 1 parameter
const isEven = (num) => {
	return num % 2 === 0;
};

//Must include parens for multiple parameters
const multiply = (x, y) => {
	return x * y;
};

// Must include parens for zero parameters
const greet = () => {
	console.log('HI!');
};

// ================ arrow functions implicit return ================

// "Regular" arrow function:
const square = (n) => {
	return n * n;
};
// Implicit Return, on multiple lines using parens
const square1 = (n) => n * n;

// Implicit return one-liner:
const square2 = (n) => n * n;

const nums = [ 1, 2, 3, 4, 5, 6, 7, 8 ];

// ALL THREE VERSIONS GIVE US THE SAME RESULT:
const doubles1 = nums.map(function(n) {
	return n * 2;
});

const doubles2 = nums.map((n) => {
	return n * 2;
});

const doubles3 = nums.map((n) => n * 2);

const parityList = nums.map(function(n) {
	if (n % 2 === 0) return 'even';
	return 'odd';
});

const parityList1 = nums.map((n) => {
	if (n % 2 === 0) return 'even';
	return 'odd';
});
const parityList2 = nums.map((n) => (n % 2 === 0 ? 'even' : 'odd'));

const parityList3 = nums.map((n) => (n % 2 === 0 ? 'even' : 'odd'));