*Some Helpful Methods for this Activity:*
*JSON.stringify()* (to store an object/array in localStorage, you'll need to stringify it first): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
*JSON.parse()* (converts a JSON string back into an object): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse
*Array .splice()* (add or remove items from arrays): https://www.w3schools.com/jsref/jsref_splice.asp
*Array.isArray()* (allows you to check whether a value is an array or not): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/isArray
*^^^ hint: use this to help you determine whether there is an existing array of to-dos from localStorage, or whether you need to create a brand new one*