Массивы

//var a = ['test']; //console.log(a[0]);

var a = ['+7', 987, 123, "45", '67'];

var phone = a.join(' '); //console.log(phone); // => '+7 987 123 45 67'

var a2 = phone.split(' '); //console.log(a2);

var a_reverse = a.reverse(); // Меняет порядок следования элементов в исходном массиве. //console.log(a_reverse); // => ["67", "45", 123, 987, "+7"] //console.log(a); // => ["67", "45", 123, 987, "+7"]

var a_sort = a.sort(); //console.log(a_sort); // => ["+7", 123, "45", "67", 987] //console.log(a); // => ["+7", 123, "45", "67", 987]

console.log(a.slice(0, 3)); console.log(a.slice(3)); console.log(a.slice(1, -1)); console.log(a.slice(-3, -2)); console.log(a);