What potential approaches could be used to achieve immutability for JavaScript arrays similar to Object.freeze() for objects?

Question

For example:

const arr = [1,2,3];
arr.slice();    //[1,2,3]
console.log(arr) //[1,2,3]

I need this array to be immutable. It should not allow adding or deleting values from the array.

Answer 1

Answer №1

When it comes to freezing objects, Object.freeze is effective on arrays too because arrays are essentially objects:

const list = [5,6,7];
Object.freeze(list);
list.push(8);    // an error will be thrown when attempting to push

Answer 2

When it comes to freezing objects, Object.freeze is effective on arrays too because arrays are essentially objects:

const list = [5,6,7];
Object.freeze(list);
list.push(8);    // an error will be thrown when attempting to push

Answer 3

Arrays, being objects, are adaptable and can be manipulated:

const myArr = [5, 6, 7];
Object.freeze(myArr);
myArr.push(8);
myArr[myArr.length - 1] = 8;

Attempting to directly change array index values may not work as expected:

const myArr = [5, 6, 7];
Object.freeze(myArr);
myArr[myArr.length - 1] = 8;

Answer 4

Arrays, being objects, are adaptable and can be manipulated:

const myArr = [5, 6, 7];
Object.freeze(myArr);
myArr.push(8);
myArr[myArr.length - 1] = 8;

Attempting to directly change array index values may not work as expected:

const myArr = [5, 6, 7];
Object.freeze(myArr);
myArr[myArr.length - 1] = 8;

Answer 5

Of course, freezing an array is possible in JavaScript. You can read more about it here.

const arr = [1,2,3];
Object.freeze(arr)
arr.push(5);

Note:- Please note that this action results in shallow freeze of the array.

const arr = [1, 2, {key: 123}];
Object.freeze(arr)
arr[2].key = 'changed value'

console.log(arr)

Answer 6

Of course, freezing an array is possible in JavaScript. You can read more about it here.

const arr = [1,2,3];
Object.freeze(arr)
arr.push(5);

Note:- Please note that this action results in shallow freeze of the array.

const arr = [1, 2, {key: 123}];
Object.freeze(arr)
arr[2].key = 'changed value'

console.log(arr)