Javascript Array Object Property Undefined

Question

When I attempt to access the array object (preivous_data) the console outputs this:

[Object { label="line1", data=[13]}]

as expected. However, when I access the array object property (preivous_data.data) the console gives undefined. I am confused - what error am I making for this not to display the array values for the property data in the object?

As a further test, I converted the object with JSON.stringify, then back into a JavaScript object. Again I found the same issues with accessing the property value of the object:

function dataUpdate(passed_onDataReceived_data){
 console.log("passed object") // console output: passed object
 preivous_data = passed_onDataReceived_data
 console.log(preivous_data) // console output: [Object { label="line1", data=[13]}]
 console.log(preivous_data.data) // console output: undefined
 var JSON_Stringify = JSON.stringify(preivous_data);
 console.log(JSON_Stringify) // console output:[{"label":"line1","data":[[0,88],[1,28],[2,52],[3,7],[4,93],[5,78],[6,53],[7,64],[8,43],[9,77],[10,58],[11,74],[12,5]]}]
 var myObject = eval('(' + JSON_Stringify + ')')
 console.log(myObject) // console output: [Object { label="line1", data=[13]}]
 console.log(myObject.data) // console output: undefined
}

Any help would be appreciated.

Answer 1

Looks like you have the object previous_data as an array.

[Object { label="line1", data=[13]}]

So you need to do previous_data[0].data to access the data attribute.

• Val: Thank you for the answer. To solve the answers while waiting for help I decided to grab copy the data attribute to a new var, then manipulate it and then update the passed_onDataReceived_data.