jQuery Storage: set default value if stored value is NaN

Question

I'm using jQuery Storage to save and restore a user's set volume level for a music player. Whenever they drag the volume slider, I save the value...

this.setVolume = function(volume) {
    ...
    $.Storage.set('volume', volume + '');
    ...
};

Then I use that value as the initial value for the slider the next time the page is loaded...

$("#volumeslider").slider({
    ...
    value: volume,
    ...
});

The saving and restoring part works fine. The problem is, if you're a brand new user and haven't yet adjusted the volume slider, volume doesn't have a value.

So I tried using a try/catch block to set the volume at 0.6 by default, unless there was a saved value to restore:

var volume = 0.6;
try {
    volume = parseFloat($.Storage.get('volume'));
} catch (e) { }

But instead, volume comes back as NaN. Then I realized that there's no "error" to catch because NaN is simply the result of parseFloat on the empty value in storage.

So: how would I set a default value only for when there's nothing in storage?

score 3 · Answer 1 · answered Jul 23 '12 at 18:36

3

Why are you storing the value as string to convert it back to a number?
Nevertheless

$("#volumeslider").slider({
    value: parseFloat($.Storage.get("volume") || 0.6),
});

answered Jul 23 '12 at 18:36

Andreas

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According to the documentation, "Names and values should be strings. Some browsers may accept non-string values, but not all do." – daGUY Jul 23 '12 at 18:43
@daGUY I must admit that I haven't read the documentation... Never mind me asking :) – Andreas Jul 23 '12 at 18:50

score 1 · Answer 2 · edited May 23 '17 at 12:00

1

Solved it using this question as a reference:

if (!isNaN(parseFloat($.Storage.get('volume')))){
    var volume = parseFloat($.Storage.get('volume'));
} else {
    var volume = 0.6;
}

edited May 23 '17 at 12:00

Community

1
1

answered Jul 23 '12 at 19:15

daGUY

27,055
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score 0 · Accepted Answer · answered Jan 22 '13 at 17:27

A cleaner solution than my original answer:

var volume = parseFloat($.Storage.get('volume'));
if (!volume) {
    volume = 0.6;
    $.Storage.set('volume', volume + '');
}

Use a stored value if it exists; if not, set a default value and store that instead.

jQuery Storage: set default value if stored value is NaN

3 Answers3