How to easily truncate an array with JavaScript?

There is a slice method

let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
arr = arr.slice(0, 4);
console.log(arr);

Will return the first four elements.

Don't forget to assign it back to your variable if you want to discard the other values.

Note: This is just regular javascript, no need for jquery.

If you're asking how to truncate (modify an array by removing the elements from the end) then use splice:

var a1 = [2,4,6,8];
var a2 = a1.splice(-2,2); // a1=[2,4], a2=[6,8]

If you're asking how to retrieve a subset of an array without modifying the original, then use slice.

var a1 = [2,4,6,8];
var a2 = a1.slice(-2); // a1=[2,4,6,8], a2=[6,8]

Just remember splice modifies, slice accesses. Negative numbers as first arg indicate index from the end of the array.

If you want to both get the elements as well as remove them from the array, use splice.

If you want to keep the elements in the array, use slice

If you want to selectively pull elements out of an array, you can use the jQuery.grep method.

(from the jQuery docs)

var arr = [ 1, 9, 3, 8, 6, 1, 5, 9, 4, 7, 3, 8, 6, 9, 1 ];

$("div").text(arr.join(", "));

arr = jQuery.grep(arr, function(n, i){
  return (n != 5 && i > 4);
});

$("p").text(arr.join(", "));

arr = jQuery.grep(arr, function (a) { return a != 9; });
$("span").text(arr.join(", "));

If you are using a take(3), I'm going to assume the array is originally being defined as the argument 3

const result = new Array(3) 
// result = [undefined , undefined , undefined]

If you iterator only returns 2 values, or the values are filtered after the take(3) command and 1 of your values is removed the array would look like

//result = [1 , 1 , undefined]

so to truncate the array of empty elements you can use

 result.filter((value) => value !== undefined);