Adding & Removing

These methods change the array in place. The mutating ones (append, prepend, insert, swap) return the modified array. pop and shift return the removed element.

.append(item) - mutates

Adds item to the end.

.prepend(item) - mutates

Adds item to the front.

arr = [2, 3]
void arr.append(4)   // arr is now [2, 3, 4]
void arr.prepend(1)  // arr is now [1, 2, 3, 4]

append and prepend return the same array reference, so they can be chained - each call mutates the original array, and pop/shift can end the chain:

arr = []
arr.append(1).append(2).append(3)  // arr is now [1, 2, 3]
log arr.append(4).pop()            // 4, arr is now [1, 2, 3]

.insert(index, item) - mutates

Inserts item before position index (1-indexed).

arr = [1, 3, 4]
void arr.insert(2, 2)  // arr is now [1, 2, 3, 4]

.swap(i, j) - mutates

Swaps the elements at positions i and j (1-indexed).

arr = [1, 2, 3]
void arr.swap(1, 3)  // arr is now [3, 2, 1]

.pop() → unknown

Removes and returns the last element.

.shift() → unknown

Removes and returns the first element.

arr = [1, 2, 3]
log arr.pop()  // 3, arr is now [1, 2]

.delete(item) → array

Removes item from the array and returns the modified array.

.trim(start, end) → array

Returns the slice from position start to end (inclusive, 1-indexed).

log [1, 2, 3, 4, 5].trim(2, 4)  // [2, 3, 4]