Trouble with getting access to an object's property

Question

I'm having a trouble with getting access to an object's property.

Isn't it possible to get access to an object's property like this?

key["heading"]

key in the code above is a variable.

This code below is the code I'm working on right now.

alertHeading.on('blur', function(){

    var inputtedVal = $(this).val();
    var key = alertMode.val();

    chrome.runtime.getBackgroundPage(function(backgroundPage) {

        var background = backgroundPage.background;

        //(1)This works fine.
        background.setStorage(key, {heading:inputtedVal});  
        console.log(background.getStorage(key));// Object {heading: "aaa"}

        //(2)This doesn't work.
        var alertObject = background.getStorage(key["heading"]);
        console.log(alertObject);// null. I'm expecting to get "aaa".

    });

})

I think I'm making a very simple mistake which comes from my lack of javascript knowledge.

Please help me out to solve this problem.

it outputs like this. [input#alert-mode.switch, context: document, selector: "#alert-mode", jquery: "1.10.2", constructor: function, init: function…] — crzyonez777
– crzyonez777, Commented Sep 14, 2013 at 2:43

nnnnnn · Accepted Answer · 2013-09-14 02:49:29Z

4

Your key isn't an object, it's a string. It is the return from background.getStorage(key) that is an object, so you can do this:

var alertObject = background.getStorage(key)["heading"]; // note () and [] placement

// OR, in two steps:
var alertObject = background.getStorage(key);
var heading = alertObject["heading"];

EDIT:

"I haven't understood why it's not an object but a string yet"

Your key variable is set to the return from jQuery's .val() method:

var key = alertMode.val();

...which returns a string that is the value of the form element that it is called on. Add in a console.log(key) and you'll see.

edited Sep 14, 2013 at 2:49

answered Sep 14, 2013 at 2:42

nnnnnn

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2 Comments

crzyonez777 Over a year ago

Thanks!! it does work! I haven't understood why it's not an object but a string yet. But, I'll try to figure it out. I'm going to accept your answer but I need to wait for 7 more minutes until stack overflow let me do it.

crzyonez777 Over a year ago

Thank you for your edition. It helped me understand the problem.

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