Added function to save grades to local storage and load grades from storage

[Suhas-13]

Haven't done the UI yet but this adds a function to load grades from local storage and save grades back in.

I also added a method toJson to the Course class so that you can save a course object to chrome local storage.

[Suhas-13]

Made the changes you mentioned.

[gary-kim]

I think this is going very much in the right direction. I like it!

Just a couple comments on implementation.

[gary-kim]

There's a race condition here if the api does not return fast enough.
Also, the WebExtension API is promised based rather then callback based. I'd recommend turning this whole function into an async function then using await for the storage call.

Also, I just learned about the @async tag in JSDoc. Nice!

Suggested change

	/**
	* Return saved grades for specified username.
	* @param {String} username users full name
	* @returns {Course[]} list of courses objects for that user
	*/
	function getSavedGrades (username) {
	const courses = [];
	let course_list = {};
	browser.storage.local.get(["user_list"], function (data) {
	course_list = data.user_list[username].courses;
	});
	for (let i = 0; i < course_list.length; i++) {
	courses.push(new Course(course_list[i].name, course_list[i].link, course_list[i].grade, course_list[i].finalPercent, course_list[i].assignments));
	}
	return courses;
	}
	/**
	* Return saved grades for specified username.
	* @async
	* @param {String} username users full name
	* @returns {Promise<Course[]>} list of courses objects for that user
	*/
	async function getSavedGrades (username) {
	const courses = [];
	const course_list = (await browser.storage.local.get(["user_list"]))?.user_list?.[username]?.courses || [];
	course_list.forEach(course => {
	courses.push(new Course(course.name, course.link, course_list.grade, course_list.finalPercent, course_list.assignments));
	})
	return courses;
	}

[Suhas-13]

Does the saveGradesLocally function also need to be made async since it's not returning anything?

[gary-kim]

Good point, couldn't hurt.

[gary-kim]

You're not merging the user_list that is already in browser storage so I think you are overwriting for every user every time. This won't work if the system logs on for multiple users.

There's two options here. We could first get from browser storage, merge the data, then set back into browser storage, or we could do something like user_data['USERDATA_' + username], in which case, we are taking advantage of how the storage api works.

Or, if you have a better option, please say it!

[Suhas-13]

Don't we need some way of listing all the users that exist? That way for last seen grades we can just query that and list all the users/grades on the system.

[gary-kim]

We could keep a separate array in browser storage of usernames that have been saved? Just an idea.

[Suhas-13]

Does this look okay to merge?

[gary-kim]

Just noticed a couple bugs but otherwise, we should be good.

[gary-kim]

I don't think this user_list is necessary anymore.

[gary-kim]

Suggested change

	await browser.storage.local.set(user_data);
	browser.storage.local.set(user_data);

No need to await here.

[gary-kim]

Suggested change

	await browser.storage.local.set(users);
	browser.storage.local.set(users);

same as above

[gary-kim]

Suggested change

	const course_list = (await browser.storage.local.get("USERDATA_" + username));
	const course_list = (await browser.storage.local.get("USERDATA_" + username))["USERDATA_" + username] || [];

[gary-kim]

Suggested change

	const user_list = (await browser.storage.local.get("user_list"), []);
	const user_list = (await browser.storage.local.get({user_list: []})).user_list;