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javascript push associative array in another

I have two associative arrays and want to push one completely to the other.
my current code:
LT_WORK_PACKAGE.data[i].STOCK_DOCCAT = stock_data.STOCK_DOCCAT;
LT_WORK_PACKAGE.data[i].STOCK_DOCNO = stock_data.STOCK_DOCNO;
LT_WORK_PACKAGE.data[i].STOCK_ITMNO = stock_data.STOCK_ITMNO;
im looking for something like this:
LT_WORK_PACKAGE.data[i].push(stock_data);

.push is for adding items to an array. You do have an object , and to copy multiple properties into an object,you can use Object.assign:
Object.assign(
/*to:*/ LT_WORK_PACKAGE.data[i],
/*from:*/ stock_data
);

You can use LT_WORK_PACKAGE.data[i] = stock_data.
Note that the previous content (if it exists) of LT_WORK_PACKAGE.data[i] will be replaced by a reference to stock_data. Any changes made in stock_data will be done in LT_WORK_PACKAGE.data[i] If you want a copy, you can use : LT_WORK_PACKAGE.data[i] = JSON.parse(JSON.serialize(stock_data))

Deepcopying observable array knockout

I have a observable which is binded to UI, On button click i am creating a new array from observable array and doing manipulation with new array but unfortunately any changes in new array affects old array too.
I am using below code for deep copying.
var clonedArr = $.extend(true, [], masterArray());
Am i missing something. You can find jsfiddle here (https://jsfiddle.net/t5a1xfud/) for more details

You need to merge the empty array and your original array in a way that $.extend does not modify your original.
Example : https://jsfiddle.net/kyr6w2x3/18/
var newArr = [];
newArr = $.extend( [], self.Array(), newArr );

How to deep copy (or otherwise make sure the arrays aren't linked):
https://jsfiddle.net/t5a1xfud/18/
self.newItems(ko.toJS(self.existingItems()));
How to not deep copy (there are other ways too):
https://jsfiddle.net/t5a1xfud/19/
self.newItems(self.existingItems());
Note that in the second example after you use the "Copy to new" button, the arrays will be linked. They appear not to be linked, but if you alternate clicking between "Add to existing" and "Add to new" you will see that they do affect eachother. Not the case with the first example.

Copying an array of objects into another array in javascript (Deep Copy)

Copying an array of objects into another array in javascript using slice(0) and concat() doesnt work.
I have tried the following to test if i get the expected behaviour of deep copy using this. But the original array is also getting modified after i make changes in the copied array.
var tags = [];
for(var i=0; i<3; i++) {
tags.push({
sortOrder: i,
type: 'miss'
})
}
for(var tag in tags) {
if(tags[tag].sortOrder == 1) {
tags[tag].type = 'done'
}
}
console.dir(tags)
var copy = tags.slice(0)
console.dir(copy)
copy[0].type = 'test'
console.dir(tags)
var another = tags.concat()
another[0].type = 'miss'
console.dir(tags)
How can i do a deep copy of a array into another, so that the original array is not modified if i make a change in copy array.

Try
var copy = JSON.parse(JSON.stringify(tags));

Try the following
// Deep copy
var newArray = jQuery.extend(true, [], oldArray);
For more details check this question out What is the most efficient way to deep clone an object in JavaScript?

As mentioned Here .slice(0) will be effective in cloning the array with primitive type elements. However in your example tags array contains anonymous objects. Hence any changes to these objects in cloned array are reflected in tags array.
#dangh's reply above derefences these element objects and create new ones.
Here is another thread addressing similar situation

A nice way to clone an array of objects with ES6 is to use spread syntax:
const clonedArray = [...oldArray];
MDN

Easiest and the optimistic way of doing this in one single line is using Underscore/Lodash
let a = _.map(b, _.clone)

You just need to use the '...' notation.
// THE FOLLOWING LINE COPIES all elements of 'tags' INTO 'copy'
var copy = [...tags]
When you have an array say x, [...x] creates a new array with all the values of x. Be careful because this notation works slightly differently on objects. It splits the objects into all of its key, value pairs. So if you want to pass all the key value pairs of an object into a function you just need to pass function({...obj})

Same issue happen to me. I have data from service and save to another variable. When ever I update my array the copied array also updated. old code is like below
//$scope.MyData get from service
$scope.MyDataOriginal = $scope.MyData;
So when ever I change $scope.MyData also change $scope.MyDataOriginal.
I found a solution that angular.copy right code as below
$scope.MyDataOriginal = angular.copy($scope.MyData);

I know that this is a bit older post but I had the good fortune to have found a decent way to deep copy arrays, even those containing arrays, and objects, and even objects containing arrays are copied... I only can see one issue with this code is if you don't have enough memory I can see this choking on very large arrays of arrays and objects... But for the most part it should work. The reason that I am posting this here is that it accomplishes the OP request to copy array of objects by value and not by reference... so now with the code (the checks are from SO, the main copy function I wrote myself, not that some one else probably hasn't written before, I am just not aware of them)::
var isArray = function(a){return (!!a) && (a.constructor===Array);}
var isObject = function(a){return (!!a) && (a.constructor===Object);}
Array.prototype.copy = function(){
var newvals=[],
self=this;
for(var i = 0;i < self.length;i++){
var e=self[i];
if(isObject(e)){
var tmp={},
oKeys=Object.keys(e);
for(var x = 0;x < oKeys.length;x++){
var oks=oKeys[x];
if(isArray(e[oks])){
tmp[oks]=e[oks].copy();
} else {
tmp[oks]=e[oks];
}
}
newvals.push(tmp);
} else {
if(isArray(e)){
newvals.push(e.copy());
} else {
newvals.push(e);
}
}
}
return newvals;
}
This function (Array.prototype.copy) uses recursion to recall it self when an object or array is called returning the values as needed. The process is decently speedy, and does exactly what you would want it to do, it does a deep copy of an array, by value... Tested in chrome, and IE11 and it works in these two browsers.

The way to deeply copy an array in JavaScript with JSON.parse:
let orginalArray=
[
{firstName:"Choton", lastName:"Mohammad", age:26},
{firstName:"Mohammad", lastName:"Ishaque", age:26}
];
let copyArray = JSON.parse(JSON.stringify(orginalArray));
copyArray[0].age=27;
console.log("copyArray",copyArray);
console.log("orginalArray",orginalArray);

For this i use the new ECMAScript 6 Object.assign method :
let oldObject = [1,3,5,"test"];
let newObject = Object.assign({}, oldObject)
the first argument of this method is the array to be updated,
we pass an empty object because we want to have a completely new object,
also you can add other objects to be copied too :
let newObject = Object.assign({}, oldObject, o2, o3, ...)

push associative array error?

I have to push elements in an associative array from another array after some processing and I'm doing something this:
for(var i in this.aNames) {
var a = this.aNames[i];
// some processing on a
aList[i] = a;
aList.push(i);
}
But it's not giving me the proper array.
EDIT :
Here aNames is an associative array like this
'1232':'asdasdasd',
'6578':'dasdasdas'
...... and so on of about 100 elements.
I'm using for here as I want to do some changes in every element of the array.
Then I'm displaying the result array on the page but it's showing the key value together with the array data.
I.e. it should only display asdasdasd or asdasdasd but it's displaying keys too, like 1232 asdasdasd 6578 dasdasdas.

There are multiple things which may go wrong...
Primarily, make sure that this is pointing to the correct context and that this.aNames is actually returning a complex object (associative array).
Also, what's aList? Is it an array? If it is, push should append your array with the key of the current member (the member's name).
If you want to append the values of the members on your source object, you need to do something like this:
var obj = {name: 'dreas'},
arr = []; // arr is an array
arr.push(obj["name"]); // arr now contains a single element, 'dreas'
In your for..in construct, you are both adding elements to an alleged array (aList) with push but also creating new members on your array (with the subscript notation, aList[i] = "asd" since i in this case (for..in iteration) refers to the member's name).
So, what you need to do is decide if you want to add elements to an array or members to an object, not both.
If you just want to clone an array, use a for loop. If on the other hand you want to clone an object, it's not that trivial because members can also be complex objects containing their own members, and simply doing arr[i] = obj.member will only copy a pointer to arr[i] if member is a complext object, not a value type.
Just to make sure my terminology is understandable:
var anObject = {name: "dreas"},
anArray = [1,2,3];
anObject["name"] <= member (results in "dreas")
anArray[1] <= element (results in 2)

How to retain array in javascript?

Here's some code that has two arrays(np and op), one a copy of the other
However, when I modify the copy, the original is also modified!
take a look:
<script type="text/javascript">
var op=new Array(0, 0);
var np=op;
np[1]=2;
document.write(op+"<br>")
document.write(np)
</script>
Is there any way to retain the original and modify the copy?

Some of the built in Array functions will actually create a copy for you. One such is slice.
For example:
var op=new Array(0, 0);
var np= op.slice(0);
np[1]=2;
document.write(op+"<br>")
document.write(np)
Reference http://my.opera.com/GreyWyvern/blog/show.dml/1725165

You never made a copy of the array. You simply assigned the array to another variable. This does not copy in Javascript. In your example there is only one array with two variables by which you can access it. There is no built-in way to copy arrays in Javascript so you will need to write your own function to do it.
Take a look at this StackOverflow question for a hint on how to actually implement the copying of the elements in the array.

What you are doing is not creating a copy of the array, it's only creating a copy of the reference to the array, so you get two references to the same array object.
This is how you can create an actual copy of the array:
var np = op.concat();
The concat method creates a new array that is a copy of the array with any additional items added. If you don't specify any additional items you just get a copy of the array.

Array.prototype.copy = function() {
return this.slice(0, this.length);
}
Then
var op=new Array(0, 0);
var np=op.copy();
np[1]=2;
document.write(op+"<br>")
document.write(np)

You should clone the second array instead of copying it.
--- Update
If you assign an object to a variable, only the reference is copied (that means, they both point to the same data). For having an independent copy of this object you need to clone it. And there are several ways how to this, for example here is the way of cloning object using jQuery.

You can just use the native slice method which returns a copy of the array:
var np = op.slice(0,op.length);
The second parameter should be optional, but in IE I believe it is required.
Your code, complete with the change:
var op=new Array(0, 0);
var np=op.slice(0,op.length);
np[1]=2;
document.write(op+"<br>")
document.write(np)

To create a new array you might want to consider:
var op = [];

To copy an array:
var np=op.slice();
or
var np=op.concat();
concat is faster, while slice takes up one less character. Some people alias "slice" or "concat" as "copy" so that it's more obvious that you're making a copy.
No need for parameters in either case. Parameters in the slice will just make the code larger and slower.