passing a string as a parameter in javascript

Question

I have created the following function

        var jsonData = <?php echo $jsondata; ?>;                            
    var objectLength = <?php echo $lines; ?>; /*length of the object*/
    var dataArray = [];
    var objectParser = {};  
    objectParser.getArrays = function(jsonData, dataType) {
        var i = 0;                          
        stringName = dataType;      
        for (i = 0; i<=objectLength; i++) {
            dataArray.push(jsonData[i].stringName);                 
        }
        return dataArray; 
    }

    var timeStamp = objectParser.getArrays(jsonData,'timestamp');

    console.log(timeStamp);

to take in JSON data and read the data from it. My problem is that right now I am getting a

Uncaught TypeError: Cannot read property 'stringName' of undefined

in the code which I am not sure why it's happening. Doing

console.log(jsonData[0].timestamp) works just fine

Here is the json data sample [{ "timestamp": "12\/16\/2013 0:00", "curr_property": "7211", "curr_property_cost": "123", "day_property": "48", "day_property_cost": "281", "curr_solar_generating": "4958", "curr_solar_export": "0", "day_solar_generated": "33", "day_solar_export": "0", "curr_chan1": "1964", "curr_chan2": "4958", "curr_chan3": "289", "day_chan1": "13", "day_chan2": "33", "day_chan3": "1" }, ..........]

Satpal · Accepted Answer · 2014-02-18 11:46:25Z

3

Use Bracket Notation

jsonData[i][stringName]

instead of

jsonData[i].stringName

Although suggest that jsonData[i] undefined. Your way to access the property is incorrect

EDIT

Also be careful with the condition i<=objectLength, Make sure objectLength is <= jsonData.length

edited Feb 18, 2014 at 11:46

answered Feb 18, 2014 at 11:28

Satpal

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Comments

Tobia · Accepted Answer · 2014-02-18 11:28:40Z

1

Cannot read property 'stringName' of undefined means that the previous operation gave an undefined value instead of an object.

The operation that comes right before .stringName is jsonData[i], so this menas that i points to an index that doesn't exist in the JSON.

This is probably due to your loop, which goes from 0 to objectLength included. I would change that.

Also, @Satpal's answer applies too.

answered Feb 18, 2014 at 11:28

Tobia

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3 Comments

Bazinga777 Over a year ago

datatype of objectLength is set to number and console.log(jsonData[somerandomno].timestamp) also works. What could be the problem ?

Tobia Over a year ago

@Bazinga777 One of the problems is that your upper index limit is included (≤), the other is an incorrect usage of object property access. Again, read our two answers.

Bazinga777 Over a year ago

Thanks, the problem was with the upper limit of the objectlength.

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