regular-functions-example.js

const multiply = function(a, b) {
	return a * b;
}

multiply(3, 5);
// output: 15

multiply(2, 40);
// output: 80

// ---------------------------

const filtered = function(arr) {
	return arr.filter(function(val) {
		return val > 4;
	})
}

filtered([1, 2, 3, 4, 5, 6, 7, 8, 9]);
// output: [5, 6, 7, 8, 9]

filtered([1, 2, 3, 4]);
// output: []

// ---------------------------

const double = function(arr) {
	return arr.map(function(val) {
		return val * 2;
	})
}

double([1, 2, 3, 4, 5, 6, 7, 8, 9]);
// output: [2, 4, 6, 8, 10, 12, 14, 16, 18]

// ---------------------------

const isThere = function(name) {
	const arr = ["Erik", "Elma", "Muz", "Kavun"];
	return arr.some(function(val) {
		return val === name;
	})
}

isThere("Elma");
// output: true

isThere("Çilek");
// output: false