The getItem function may return incorrect values

[pitAlex]

Hi,

I see you are doing this:

      getItem: function (name) {
            if (localStorageData[name]) {
                return localStorageData[name];
            }
            return null;
        }

However if localStorageData[name] is 0, false or "" then getItem(name) will return null. You should change it something like this:

      getItem: function (name) {
            if (localStorageData.hasOwnProperty(name)) {
                return localStorageData[name];
            }
            return undefined; // null can also be intentionally set so its best to just give "undefined"
        }

Update: In fact I don't see any harm in just doing :

      getItem: function (name) {
            return localStorageData[name];
        }

If the key doesn't exist the result will be "undefined".

[NathanaelA]

Good catch!

[terreb]

I hit the issue related to this. I need to store an empty string value. getItem returns null however should return ''.

[DanielKucal]

I think the result of getting not-existing variable should be null, just like in web browsers. There is no way for local- and sessionStorage to return undefined... @terreb, have you tried to JSON.stringify() the data before save and then JSON.parse() to get the desired value? This is how frontend libraries handle it. If you are writing Angular app, then you can also try my lib ngx-store when #9 will be merged.

[NathanaelA]

@DanielKucal - Your are correct, null is what is supposed to be returned when it doesn't exist. I will update the getItem function to return null rather than undefined. Thanks.

[terreb]

@DanielKucal, why would I need to JSON.stringify a string?

[DanielKucal]

@terreb, in general you should not, but there was a bug about it and I think I've also noticed some issue with it recently... It was like some value was changing after site reload. However I agree that localStorage.setItem('test', ''); localStorage.getItem('test')) should return "".

[NathanaelA]

The newest published version has both this fix (null instead of undefined). And your patch for Storage object..