We Keep Coding

Javascript: Save variable field names

I have 2 strings. One represents the variable name and the other the value.
This might explains it better:
var data = ['varName', 'content'];
var obj = { data[1]: data[2] }
The other post I've found yet only refer to an objects name.

You can set it like this:
var data = ['varName', 'content'];
var obj = {};
obj[data[0]] = data[1];

Javascript multidimensional array not working

How to create multidimensional array??
I tried it so far:
var post_data = [];
var id = 1;
post_data[id] = [];
post_data[id]['name'] = 'abc';
post_data[id]['date'] = '01-03-2014';
post_data[id]['country'] = 'India';
console.log(post_data);
the above code is not giving me the key. Whats wrong?
DEMO FIDDLE
i want a output something like this:
[1]=> array
(
"name": "abc",
"date": "01-03-2014",
"country": "India",
)
How to get the above output???

To get wished result you can change
var post_data = [];
to
var post_data = {};
and
post_data[id] = {};

You are trying to make an array of object.
Try this : -
post_data[id] = {};

You are using the inner array as an object. The properties that you set on the array still is there, when you display it only the array items are shown.
You should use an object instead of an array, as you are not using the array as an array:
post_data[id] = {};
Instead of setting the properties after creating the object, you can set them when you create it:
post_data[id] = {
name: 'abc',
date: '01-03-2014',
country: 'India'
};

In the third line of code you have to write
post_data[id] = new Array();
So the entire code section looks like
var post_data = [];
var id = 1;
post_data[id] = new Array();
post_data[id]['name'] = 'abc';
post_data[id]['date'] = '01-03-2014';
post_data[id]['country'] = 'India';
console.log(post_data[id]['name']);
This should fix it, best of luck :)

Javascript create object with property as dynamic objects

I tried a lot searching and didnt get desired solutions.
What I want to achieve is
var myObject {
id1 : {
name:place_name,
location : place_loc
},
id2 : {
name:place_name,
location : place_loc
},
id3 : {
name:place_name,
location : place_loc
}
}
What I want to do is that Initially I want the properties "id1", "id2".. to be dynamic. And then dynamically assign name:place_name and other properties of each property.
I dont know the number of properties (id1,id2,id3...) hence would like to add them dynamically and following the addition of properties(id1,id2... ) I want to dynamically add the property values. (place_name & place_loc) of each id.
My code looks something like this.
var myObject = {};
myObject[idnumber1].place = "SomePlace1";
myObject[idnumber1].place = "SomeLoc1";
myObject[idnumber2].place = "SomePlace1";
myObject[idnumber2].place = "SomeLoc1";
But it gives error.
I know it seems simple doubt but any help would be grateful.
Thanks in advance. :)

You are trying to set a value of already assigned objects at keys "idnumber1", etc.
What you'll need is to initialize each objects for your ids like this:
var myObject = {};
myObject[idnumber1] = {};
myObject[idnumber1].place = "SomePlace1";
myObject[idnumber2] = {};
myObject[idnumber2].place = "SomeLoc1"

I would do it this way, it's not exactly what you did ask for, but I think it will become easier to change this later on.
function Place(name, location) {
this.name = name;
this.location = location;
}
var myObject = {}
myObject['id1'] = new Place('Foo', 'Bar');
myObject['id2'] = new Place('Internet', 'test');
console.log(myObject);

To dynamically create objects in your collection, you can use a numerical counter variable to create your object collection (myObject["id" + i] = {name: place_name, location: place_loc}).
An example:
var myObject = {};
for (i = 0; i < 20; i++){
myObject["id" + i] = {name: place_name, location: place_loc}
}
In practice, you can use a counter that you increment outside of a loop.

Setting dynamically an Object in JavaScript

It seems complicated for me.
First, I have this list:
liste_path_categories.push(
{ index: null
, letter: "letter1"
, type: key
, picture_url: "url1"
, id_categ: null
, response: "Answer here"
});
What I want is to extract from this big list an object in this form:
data["String1"]["String2"]= String3
With :
String1=list_path_categories[i].letter
String2=list_path_categories[i].id_categ
String3=list_path_categories[i].response
example:
data['A']['12'] : "A_answer"
To declare the data i make this:
var data = new Object(new Object);
How I can set all the values in data?

You can use the Array.forEach method to iterate through liste_path_categories and construct your data object.
Example:
var liste_path_categories = [];
var data = {};
liste_path_categories.push(...);
...
liste_path_categories.push(...);
liste_path_categories.forEach(function(element) {
data[element.letter] = {};
data[element.letter][element.id_categ] = element.response;
});
jsFiddle example : http://jsfiddle.net/3ZvNf/

Your question is pretty vague but do you mean something like this?
Setting a dynamic property in an object wich belongs to another object?
data['A']['12'].answer = "A_answer"

Instead of using strings, you have to use the variables in your property access:
var data = {};
if (!data[String1]) {
data[String1] = {}; // make sure that data[String1] exists and is an object
}
data[String1][String2] = String3;
If you want to do this for elements in the array, you have to iterate over the array.
P.S.: I recommend to use more expressive variable names than StringX.

first create the constructor (in OOP terminology):
var ctor_object = function(letter,id_categ,response)
{
this.letter = letter;
this.id_cated = id_categ;
this.response = response;
}
(in genereal you should omit the ctor_ syntax and name it directly after the name of the class of your object)
then use your constructor upon your list of categories:
var length = liste_path_categories.length,
element = null;
for (var i = 0; i < length; i++)
{
element = liste_path_categories[i];
my_obj = new ctor_object(element.letter,element.id_categ,element.reponse)
// Do something with my_obj
}

javascript how to find number of children in an object

is there a way to find the number of children in a javascript object other than running a loop and using a counter? I can leverage jquery if it will help. I am doing this:
var childScenesObj = [];
var childScenesLen = scenes[sceneID].length; //need to find number of children of scenes[sceneID]. This obviously does not work, as it an object, not an array.
for (childIndex in scenes[sceneID].children) {
childSceneObj = new Object();
childSceneID = scenes[sceneID].children[childIndex];
childSceneNode = scenes[childSceneID];
childSceneObj.name = childSceneNode.name;
childSceneObj.id = childSceneID;
childScenesObj .push(childSceneObj);
}

The following works in ECMAScript5 (Javascript 1.85)
var x = {"1":1, "A":2};
Object.keys(x).length; //outputs 2

If that object is actually an Array, .length will always get you the number of indexes. If you're referring to an object and you want to get the number of attributes/keys in the object, there's no way I know to that other than a counter:
var myArr = [];
alert(myArr.length);// 0
myArr.push('hi');
alert(myArr.length);// 1
var myObj = {};
myObj["color1"] = "red";
myObj["color2"] = "blue";
// only way I know of to get "myObj.length"
var myObjLen = 0;
for(var key in myObj)
myObjLen++;