Added helpers to handle non-stringified values when parsing keys from localStorage

[sreeram-venkitesh]

Fixes #661

Changes made

• Added localStorage helper at javascript/src/helpers/storage.js, similar to what is done in granite
• Added check inside getFromLocalStorage method to check if existing value is JSON stringified. If not, the value is replaced with null.
• Replaced all existing localStorage.setItem() and localStorage.getItem() with setToLocalStorage() and getFromLocalStorage() methods from the helper.

@yedhink _a

[yedhink]

@sreeram-venkitesh _a

I have added some comments. Please go through them and let me know if you need any clarifications.

[yedhink]

@sreeram-venkitesh Also, the title of the PR needs to be in the past tense. We don't follow imperative present tense in commit messages nor PR titles.

I always give this reference to someone who starts new and is working with me: https://github.com/bigbinary/bigbinary-website/pull/781#pullrequestreview-677312016

PS: If we need to discuss or bring something to my attention or need my help, then the review comment can be left unresolved.

[sreeram-venkitesh]

@yedhink _r

I have added the following changes as per your comments

• Added storedValue variable
• Removed redundant JSON.parse()

I have added a reply in the comment about adding logger.error() statement. Please review it. Thank you

[yedhink]

@sreeram-venkitesh _a

LGTM.

One last thing, verify the following with this PR:

• Open Granite in localhost:3000. Log in. But don't log out.
• Close the server
• Open Wheel in localhost:3000. Try to log in.
• Expectation is that we are able to open up wheel without any issues.

Once you've verified, you can assign me using _a syntax. Note: It's _a and not _r. There is no macro for _r. All these macros are defined in our own gitemit bot.

The idea is that we assign the PR back if the merging of the PR now falls in the hand of someone else. Assigning to someone else means my assigned task has been done. For asking queries we don't assign, but rather mention.

cc: @AbhayVAshokan @subins2000 @jagannathBhat @prasidhprabudhan You folks might've encountered a similar error while setting up wheel. Once this PR is merged to wheel, make sure you pull the latest from wheel.

[yedhink]

@sreeram-venkitesh _a

Noticed this now. One more minor change is required.

[sreeram-venkitesh]

@yedhink _a

Changed the order of the return statement as mentioned in the review, in my last commit.

I also tried the steps you mentioned and tried switching from granite to wheel. Once I started wheel's server, reloading the logged in granite page gave the home screen for wheel. This is the intended behaviour if we already have authToken and authEmail stored from a different project.

Please review the changes. Thank you.