function for array returns null

Question

The below function returns this output. But I can't understand why. Any clues? Output: {"A":{"antal":null},"B":{"antal":null},"C":{"antal":null},"D":{"antal":null},"E":{"antal":null},"G":{"antal":null}}

Function is,

    function seriestat(){
        var statserier = {};

        $.each(globalSIEdata["#EXTRA"]["VERSERIER"], function(i, item) {
                    statserier[i] = {};
        });
        $.each(globalSIEdata["#VER"], function(i2, item2) {
                var serie = i2.substring(0, i2.indexOf('-')); 
                statserier[serie]["antal"] += 1;
        });
        return statserier; 
    }

Here is example from globalSIEdata:

{    "#VER": {
    "A-1": {
        "verdatum": "2017-01-03"
    },
    "A-2": {
        "verdatum": "2017-01-03"
    },
    "B-1": {
        "verdatum": "2017-01-03"
    },
    "B-2": {
        "verdatum": "2017-01-03"
    }
    "A-3": {
        "verdatum": "2017-01-03"
    }

}

You don't understand why a function that creates and populates an object returns an object? — Andy
– Andy, Commented Oct 7, 2017 at 15:47
what does globalSIEdata looks like? can you share some sample/minimal data for review/testing? — palaѕн
– palaѕн, Commented Oct 7, 2017 at 15:51
What is expected result of statserier[serie]["antal"] += 1? — guest271314
– guest271314, Commented Oct 7, 2017 at 15:51
You got to be setting null somewhere else, there's no way += 1 would ever get you null — MinusFour
– MinusFour, Commented Oct 7, 2017 at 15:54
Added example from globalSIEdata above. Want to count the number of lines per object where item begins with A, B, C etc. — Kevin Lindmark
– Kevin Lindmark, Commented Oct 7, 2017 at 15:59

justadudewhohacks · Accepted Answer · 2017-10-07 16:06:13Z

3

You forgot to initialize the "antal" property thus it will be undefined, try something like:

statserier[serie]["antal"] = (statserier[serie]["antal"] || 0) + 1;

Alternatively you could try to initialize your statserier object as follows instead:

statserier[i] = { antal: 0 };

edited Oct 7, 2017 at 16:06

answered Oct 7, 2017 at 15:51

justadudewhohacks

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2 Comments

MinusFour Over a year ago

undefined + 1 would get you NaN and he's getting null

justadudewhohacks Over a year ago

Well the output he posted is stringified, and NaN stringified is null.

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