JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr = [1, 2, 3];
var arr2 = [1, 4, 9];

Array.prototype.power = function(value) {
    for (var i = 0; i < this.length; i++) {
        this[i] = Math.pow(this[i], value);
    }
    return this;
}

Array.prototype.compare = function(value) {   
    if (this.length !== value.length) {
         return false   
    }
    
    for (var i = 0; i < this.length; i++) {
        if (this[i] !== value[i]) {
         return false;   
        }
    }
    
    return true;
}

var convertedArray = [1, 2, 3].power(2);
var isEqual = convertedArray.compare(arr2);

console.log(convertedArray);
console.log(isEqual);