FAQ: Arrays - Arrays with let and const


This community-built FAQ covers the “Arrays with let and const” exercise from the lesson “Arrays”.

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This exercise can be found in the following Codecademy content:

Web Development

Introduction To JavaScript

FAQs on the exercise Arrays with let and const

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I just completed the " Arrays with let and const" section and I must say I don’t get the explanation that says : " However, if a const variable contains an array, you can mutate elements in the array but not re-assign an new value!"
–> What we were asked to do in the exercice consisted (to me) to reassign a value to an element stored in a const variable… Which is way I don’t get the subtelty between “mutating” an element and “re-assigning it a new value”. Can someone help me on this ? :slight_smile:


lets do analogy, lets say you build a house (which represents a an array declared with constant):

const myHouse = ['living_room', 'bath_room', 'kitchen'];

you can perfectly change things in the house, add a dishwasher for example:

const myHouse =  ['living_room', 'bath_room', 'kitchen'];

however, you can’t just replace the house:

const myHouse = ['living_room', 'bath_room', 'kitchen'];
myHouse = ['new_house']; // error

so that is the difference between mutation (manipulating the array itself), and re-assigning the variable.


Hello, i was working with let and const but i deleted the elements in the condiments array. I restored my worksheet but it didn’t restore to the original array but the one i deleted. Kindly help with the elements in the condiment array!!!


Here is what comes up in the lesson, for me. Is this what you are looking for?

let condiments = ['Ketchup', 'Mustard', 'Soy Sauce', 'Sriracha'];