This question already has answers here:
Accessing an object property with a dynamically-computed name
(19 answers)
Closed 4 years ago.
I have:
Main.children.firstfunction.isEnabled = true;
Main.children.second.isEnabled = true;
Main.children.gsdfgsg.isEnabled = true;
Main.children.other.isEnabled = true;
All of these is working good, but such calls is a lot of, so I have in array:
var names = ['firstfunction', 'second', 'gsdfgsg', 'other'];
And I would like do:
for (var name in names) {
Main.children.name.isEnabled = true;
}
But of course it does not work. How can I improve it?
Use bracket ([]) notation. This will allow you to evaluate the property names dynamically.
Try
for (var name in names) {
Main.children[name].isEnabled = true;
}
Related
This question already has answers here:
How to use a variable for a key in a JavaScript object literal?
(16 answers)
Closed 4 years ago.
I have a series of variables that I would like to pass into an object and I need the left side key to be pulled from a dynamic variable. How would I go about doing this?
Here's an example:
var characteristic = 'color';
var value = 'green';
// Desired JSON output
var object = {
color: 'green'
}
like so:
var characteristic = 'color';
var value = 'green';
var object = {
[characteristic]: value
}
console.log(object);
This question already has answers here:
How to use a variable for a key in a JavaScript object literal?
(16 answers)
Closed 5 years ago.
I need an object in Typescript declared like this:
queryParameters = { flagged: true };
Now I would like to have the flagged to be retrieved from a variable name. Something like:
var param = 'flagged';
queryParameters = { ValueOf(param): true };
Any idea ?
Thanks.
Why not use computed property names:
queryParameters = { [param]: true };
This question already has answers here:
JavaScript object: access variable property by name as string [duplicate]
(3 answers)
Closed 6 years ago.
I guess I didnt really know how to ask this question for me to find an answer.
So I have three variables that are going to make this function do what it has to
function gatherDataForGeographic(ele) {
var $this = $(ele)
var $main_title = $this.find('.options-title'),
$option = $this.find('.option');
var arr = []
var reportAreas = reportManager.getReportAreasObject();
$option.each(function () {
var $this = $(this)
var $checkbox = $this.find('.checkbox');
var type = $this.data('type'),
index = $this.data('index');
if ($checkbox.hasClass('checkbox--checked')) {
console.log(reportAreas.type)
} else {
return true;
}
})
return arr;
}
//this will return an object that I need to index
var reportAreas = reportManager.getReportAreasObject();
//this will get the a key that i need from the object
var type = $this.data('type');
//this will give me the index I need to grab
var index = $this.data('index');
So what I am trying to do is go through the object based on the type(or key) from the option selected by a user
The problem...
It is looking for reportArea.type[index] and is not recognizing it as a variable and I keep getting undefined because .type does not exist.
Is there a way for it to see that type is a variable and not a key?
You can use dynamic properties in JS using the bracket syntax, not the dot syntax:
reportAreas[type]
That will resolve to reportAreas['whateverString'] and is equivalent to reportAreas.whateverString- reportAreas.type however, is a literal check for type property.
reportArea[type][index]
JavaScript objects are just key-value pairs and the dot syntax is just syntactic sugar for the array notation.
object['a']
and
object.a
Are the same thing, basically.
This question already has answers here:
Use a concatenated (dynamic) string as JavaScript object key? [duplicate]
(6 answers)
Closed 8 years ago.
I am trying to add a property to an object, but Dot notation can't handle a string.
my object:
var lists = {
"Cars":{"Ford":false,"Ferarri":false},
"Names":{"John":true,"Harry":false},
"Homework":{"Maths":true,"Science":false,"History":true,"English":true}
}
Adding a property:
function add_item() {
var input = "Alfa Romeo";
var command = eval('lists.Cars.' + input + '=false');
}
How can I do this using Bracket Notation seeing as it's a 2D object?
No need for eval.. and blah is undefined in your example.
var lists = {
"Cars":{"Ford":false,"Ferarri":false},
"Names":{"John":true,"Harry":false},
"Homework":{"Maths":true,"Science":false,"History":true,"English":true}
}
function add_item(key, value) {
lists.Cars[key] = value;
}
add_item('Alfa Romeo', true);
console.log(lists);
This question already has answers here:
How to create an object property from a variable value in JavaScript? [duplicate]
(9 answers)
Accessing an object property with a dynamically-computed name
(19 answers)
Closed 8 years ago.
I need to figure out how to create a dynamic key string for an object. This expression makes JavaScript complain.
return {$(this).val(): true}; // returns an object e.g. {2: true}
What am I doing wrong?
You have to create the object, then use bracket notation for the dynamic key
var obj = {};
var val = $(this).val();
obj[val] = true;
return obj;
or a completely unnecessary one-liner
return (function(o,e) {o[e.value]=true; return o;})({}, this);
The JavaScript object literal syntax {x: y} specifies that x will be a (possibly) quoteless string, and y any value. You can't use this syntax for dynamic keys.
Use this instead:
var foo = {};
foo[$(this).val()] = true;
return foo;