Calling javascript object's own properties

Question

I have this object 'cp'. and it has got some properties like labels and arcSettings in it. Whenever i initialize this object and call the method 'graph()' it says

Uncaught TypeError: Cannot read property '0' of undefined

Am I doing something wrong?

function cp() {             
        this.labels = [{
            "pointThickness": 0.8,
            "distance": 8,
            "textDistance": 7,
            "strokeColor": "#888",
            "strokeWidth": 0.5,
            "textColor": "#777",
            "pointColor": "#888",
            "textSize": 4,
            //"interval":100,
            //"precision":2,
            "num": 10,
            "startValue": 0,
            "endValue": 300
        }
        ];

        this.arcSettings = [
            {
               "totalArcAngle":300,
                "startAngle":(-this.totalArcAngle/2),
                "endAngle":(this.totalArcAngle/2),
                "progressValue":200,
                "radius":150,
                "thickness":30,
                "displayValue":this.progressValue
            }
        ];                   
}

cp.prototype.getOneUnit = function () {
    return oneUnit = (this.arcSettings[0].totalArcAngle) / (this.label[0].endValue - this.label[0].startValue);

}

cp.prototype.graph= function(){                     
var oneUnit = this.getOneUnit();

}

var cp = new cp();
cp.graph();

Zero Fiber · Accepted Answer · 2014-01-24 10:59:37Z

2

In the cp.prototype.getOneUnit function, you are using this.label. Instead, it should be this.labels.

cp.prototype.getOneUnit = function () {
    return oneUnit = (this.arcSettings[0].totalArcAngle) / (this.labels[0].endValue - this.labels[0].startValue);
}

answered Jan 24, 2014 at 10:59

Zero Fiber

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Comments

The Alpha · Accepted Answer · 2014-01-24 11:01:21Z

2

At first make an instance of the object

var cp = new cp();

Then add methods/properties into prototype

cp.prototype.graph= function(){ }

Also, you have used same name in both Class/Function declaration and object instance variable. You may change function cp() to function Cp().

answered Jan 24, 2014 at 11:01

The Alpha

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Comments

Serge K. · Accepted Answer · 2014-01-24 11:00:44Z

1

You just made a typo. You wrote label instead of labels.

answered Jan 24, 2014 at 11:00

Serge K.

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