# Possible Copy Error in Javascript Challenge Guide

I may have found a copy discrepency in " freeCodeCamp Challenge Guide: Map the Debris"

I would appreciate it if someone could check this out to confirm or correct my reading of the solution/explanation. If I’m reading this right please point me in the direction to report it. Solution 2 for the same challenge has a similar wording.

Details

In the Code Explanation for Solution 1 the last bullet states:

• Then we delete the key avgAlt , and add the new key and its value.

it seems that the code actually is creating a new array of objects and doesn’t mutate the array. Should line should be corrected to something along the lines of

• Then we add the new key: value and return the newArr.

This is the Solution in question:

``````function orbitalPeriod(arr) {
var GM = 398600.4418;
var earthRadius = 6367.4447;
var a = 2 * Math.PI;
var newArr = [];

var getOrbPeriod = function(obj) {
var c = Math.pow(earthRadius + obj.avgAlt, 3);
var b = Math.sqrt(c / GM);
var orbPeriod = Math.round(a * b);
// create new object
return {name: obj.name, orbitalPeriod: orbPeriod};
};

for (var elem in arr) {
newArr.push(getOrbPeriod(arr[elem]));
}

return newArr;
}

// test here
orbitalPeriod([{ name: "sputnik", avgAlt: 35873.5553 }]);
``````

#### Code Explanation

• GM and earthRadius are both given to us.
• To make the code easier to edit and read, each part of the equation is written separately.
• Create newArr to store the `orbPeriod` 's.
• a is 2 times pi. The part that is a constant is on the global scope while the rest is part of a function.
• Create a function, `gerOrbPeriod()` that will do the required work for any amount of objects.
• c is ( earthRadius + avgAlt ) to the cube.
• b is the square root of c divided by GM .
• Create orbPeriod to store the product of a and b , with the `Math.round()` function applied to round up to the next whole number.
• ----->>>Then we delete the key avgAlt , and add the new key and its value.

Yep, that seems like a mistake, like the description of a slightly different solution. It looks closer to solution 3. You could create an issue on the repo.

as the solutions are on the forum guide, I have just moved your post in #contributors, where all guide contributions posts are kept, someone will come along and make the change

1 Like

Great. Thanks A lot.

Fantastic, Thank you.