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How to fix Cannot read property hasOwnProperty of undefined

How to fix Cannot read property 'hasOwnProperty' of undefined?
Using Angular.JS 1.3
Assigning response data in $rootScope.settings in parentConroller.
so the rootScope will be like this
$rootScope.settings = api.data;
//sample
$rootScope.settings:{
"lastLogin":"2005-01-01",
"isStudent": true,
"assignedCourse": "['JAVA + DS']"
}
And accessing the $rootScope data in anotherController.JS. But here I don't want my array inside string, so to remove double quotes, I tried below ways
Attempt 1:
if($rootScope.settings.hasOwnProperty('assignedCourse')) {
$rootScope.settings.assignedCourse = ['JAVA + DS']
}
Attempt 2:
$rootScope.settings.assignedCourse = JSON.parse(rootScope.settings.assignedCourse.replace(/'/g, '"'));
// giving me Error: Unexpected token ' in JSON at position 1
Attempt 1 is working in the application, but its getting failed when i run karma debugger which is showing TypeError: Cannot read property 'hasOwnProperty' of undefined
Literally don't know how to fix this issue. Struggling to fix more than a days
I've already gone through few SO's related to my issues. but don't get any better solutions
Side Note: currently using only plain old JavaScript, not es6 or updated version.

For starters, you may want to be using angular.isDefined($rootScope.settings.assignedCourse) instead of hasOwnProperty as it is likely syntactically closer to what you are testing for (defined value instead of property ownership)
Regarding attempt 1 failing in the test, settings is undefined. You may need to re-examine your test bed and ensure your scope is being initialized as you expect.
I recreated your attempt 2 successfully, I suspect something else is going on here and may be resulting from another line.

Pass Component Name as Argument and then attach method (not working?)

Maybe I'm not using the right terms/names for my searches but I have not been able to find anything on this topic. I would have thought this would be an easy thing to find. What I'm doing is passing a component name to a function and then trying to use the component's name by attaching a method to it. I have confirmed (via Dev Tools) that the name is correctly being passed but when I use the variable and attach the method the specific request does not work. If I 'hard-code' the exact component name to the method it works perfectly. This makes me think the (various) ways I've been trying to attach the method to the variable name is incorrect (see various attempts below). Can you offer some direction here? Thank you.
Passing to Function ...
const grid_name = "grid_GroupA";
console.log(grid_name); // Shows grid_GroupA
msg_max(newItem, grid_name);
Function (only listing relevant parts)
function msg_max(newItem, grid_target) {
console.log(grid_target); // Shows grid_GroupA
// grid_GroupA.data.add(newItem); // This works ...
// grid_target.data.add(newItem); // This does not work
// (grid_target).data.add(newItem); // This does not work
// [grid_target].data.add(newItem); // This does not work
// grid_target + '.data.add(newItem)'; // This does not work
Thank you ...
Edit ...
In my attempt to provide detail I hope I haven't confused the issue.
In essence, my question is if I can type this exact string
grid_GroupA.data.add(newItem);
and it works for my function, how can I place a variable with the exact string "grid_GroupA" in front of ".data.add(newItem);" and have it seen the same as the line of code that works? Maybe my lack of knowledge here is getting in the way but isn't the line of code that works just a string that is then used to 'find' the object? So, if that assumption is correct, how do I create that same string with the variable? If my assumption is wrong I am a willing learner so I will be all ears. Thank you.

I do not see how grid_target is an object. You are passing grid_name(which is a string) to the function, so grid_target will have no data property, because string doesn't have such a member.
P.S. snake_case is bad option for JavaScript, consider using cameCase instead

JSON return error as undefined when the value is numeric

not sure where the errors lies in what I am trying to achieve.
I am working with someone else's code and unfortunately they have used numbers for div ids in some places.
These number ids are used in various places and if I can, I want to find a way to keep things as they are.
So,
returning the following in JSON:
editorID: "1000"
And in my AJAX call i use that return like so:
var editorID = response.editorID;
CKEDITOR.instances.editorID.insertHtml('<br><img class="buildimage" src="http://www.buildsanctuary.com/phpLibs/bulletproof-master/src/userBuildImages/'+response.imageName+'"><br>');
However this gives me an error saying that the editorID is undefined.
As you can I already use a JSON response in my code, this works fine so its not a problem with datatypes etc.
I also tried to do:
alert(response.editorID);
which gave me the correct value.
When I tried putting a number directly into CKEditor insertHTML code it was showing my syntax errors so maybe thats the issue. If so, any work around for it?
Thanks. Craig.

To use a variable as a property, you have to use [] notation:
CKEDITOR.instances[editorID].insertHtml('<br><img class="buildimage" src="http://www.buildsanctuary.com/phpLibs/bulletproof-master/src/userBuildImages/'+response.imageName+'"><br>');
When you use .editorID, it's looking for a property named editorID, not 1000.
You also have to use this syntax when the property isn't a valid identifer. So if you wanted to put the number directly, you would write:
CKEDITOR.instances['1000'].insertHtml('<br><img class="buildimage" src="http://www.buildsanctuary.com/phpLibs/bulletproof-master/src/userBuildImages/'+response.imageName+'"><br>');

Javascript json, check all keys for undefined ('null') and set default

Firstoff I'd like to add I've been learning javascript for like only 2 days now. I'm pretty much way ahead of myself with what I'm trying to get but here goes.
I have a json array from which I get data to replace/insert in my page. The first problem I have is that if it comes across an empty ('null') key it will just stop. Will not even try to continu.
document.getElementById("id1")src=json.img1.link;
document.getElementById("id2")src=json.img2.link;
document.getElementById("id3")src=json.img3.link;
json.img2.link is empty ('null' response from json.). javascript will then not replace "id2" but it also won't replace "id3".
I'm now trying to find a solution where it will if nothing else at least set a default.

The script is not continuing executing because it comes to an error --trying to access property link of an undefined object
Try
document.getElementById('id2').src = json.img2 ? json.img2.link : 'defaultLink';
This way your are checking for undefined (ie null) object in img2 and assigning the default value. This assumes that what is not defined (null) is the img2 object.

Actually I don't think your code should work at all, you are missing the. before the src So, try
document.getElementById("id1").src=json.img1.link;
document.getElementById("id2").src=json.img2.link;
document.getElementById("id3").src=json.img3.link;
and let us know if that doesn't solve the problem.
Btw, +points for learning JavaScript and not just straight into jQuery!

JavaScript if statement returns wrong values

Does anybody knows why this snippet returns false even if the passed string is "Active"?
if ($('status_'+id).getText()=="Active")
I've also tried changing the code to
if ($('status_'+id).getText()==String("Active"))
and
if (String($('status_'+id).getText())=="Active")
and still no luck.
I've also checked $('status_'+id).getText() through console.log to verify if it really returns "Active"
i wonder why it doesnt work?
any ideas?

Silly question: are you sure the returned string doesn't contain spaces?

The first step in any debugging task is to check your assumptions. Use a debugger or a series of alerts to check the following:
what's the value of id?
does$('status_'+id) evaluate to a DOM
element?
what does
$('status_'+id).getText() actually
return