Example 1: js array return only certain positions
const every_nth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1);
console.log(every_nth([1, 2, 3, 4, 5, 6], 1));
console.log(every_nth([1, 2, 3, 4, 5, 6], 2));
console.log(every_nth([1, 2, 3, 4, 5, 6], 3));
console.log(every_nth([1, 2, 3, 4, 5, 6], 4));
// OUTPUT
[1,2,3,4,5,6]
[2,4,6]
[3,6]
[4]
Example 2: javasript array indexof
var array = [2, 9, 9];
array.indexOf(2); // 0
array.indexOf(7); // -1
array.indexOf(9, 2); // 2
array.indexOf(2, -1); // -1
array.indexOf(2, -3); // 0
Example 3: check items in array javascript
function checkAllEven(arr) {
return arr.every(function(x){
return x % 2 === 0
})
}
//using "every" to check every item in array.
Example 4: array of in javascript
The Array. of() method creates a new Array instance from a variable number of
arguments, regardless of number or type of the arguments. The difference between
Array. of() and the Array constructor is in the handling of integer arguments: Array.