It's not an array.

var json = {"cool":"34.33","alsocool":"45454"};
json.coolness = 34.33;

or

var json = {"cool":"34.33","alsocool":"45454"};
json['coolness'] = 34.33;

you could do it as an array, but it would be a different syntax (and this is almost certainly not what you want)

var json = [{"cool":"34.33"},{"alsocool":"45454"}];
json.push({"coolness":"34.33"});

Note that this variable name is highly misleading, as there is no JSON here. I would name it something else.

Array.prototype.push(), The arr.push() method is used to push one or more values into the array. This method changes the length of the array by the number of elements� The push() method adds one or more elements to the end of an array and returns the new length of the array.

var array = new Array(); // or the shortcut: = []
array.push ( {"cool":"34.33","also cool":"45454"} );
array.push (  {"cool":"34.39","also cool":"45459"} );

Your variable is a javascript object {} not an array [].

You could do:

var o = {}; // or the longer form: = new Object()
o.SomeNewProperty = "something";
o["SomeNewProperty"] = "something";

and

var o = { SomeNewProperty: "something" };
var o2 = { "SomeNewProperty": "something" };

Later, you add those objects to your array: array.push (o, o2);

Also JSON is simply a string representation of a javascript object, thus:

var json = '{"cool":"34.33","alsocool":"45454"}'; // is JSON
var o = JSON.parse(json); // is a javascript object
json = JSON.stringify(o); // is JSON again

JavaScript Array push() Method, push. The simplest way to add items to the end of an array is to use push . const zoo =� Javascript array push() method appends the given element(s) in the last of the array and returns the length of the new array. Syntax. Its syntax is as follows − array.push(element1, , elementN); Parameter Details. element1, , elementN: The elements to add to the end of the array. Return Value. Returns the length of the new array. Example

That is an object, not an array. So you would do:

var json = { cool: 34.33, alsocool: 45454 };
json.supercool = 3.14159;
console.dir(json);

5 Way to Append Item to Array in JavaScript, JavaScript gives us four methods to add or remove items from the beginning or end of arrays: pop(): Remove an item from the end of an array. let cats = ['Bob'� In this tutorial, we will demonstrate how to add single, multiple items(elements) into an array, and how to add one array to another array using the array push() and Concat() method of javaScript with examples. javaScript push() Method. The javaScript push() method is used to add new elements to the end of an array.

object["property"] = value;

or

object.property = value;

Object and Array in JavaScript are different in terms of usage. Its best if you understand them:

Object vs Array: JavaScript

Pop, Push, Shift and Unshift Array Methods in JavaScript, Javascript array push() method appends the given element(s) in the last of the array and returns the length of the new array. Syntax. Its syntax is as follows − array� The unshift() method can be used to push to the front of array. var array2 = [array1.map(item=>[item.a, item.b])]; array2.unshift([array1[0].a, array1[0].b])

Use the push() function to append to an array:

// initialize array
var arr = [
    "Hi",
    "Hello",
    "Bonjour"
];

// append new value to the array
arr.push("Hola");

Now array is

var arr = [
    "Hi",
    "Hello",
    "Bonjour"
    "Hola"
];

// append multiple values to the array
arr.push("Salut", "Hey");

Now array is

var arr = [
    "Hi",
    "Hello",
    "Bonjour"
    "Hola"
    "Salut"
    "Hey"
];

// display all values
for (var i = 0; i < arr.length; i++) {
    console.log(arr[i]);
}

Will print:

Hi
Hello
Bonjour
Hola 
Salut
Hey

Update

If you want to add the items of one array to another array, you can use Array.concat:

var arr = [
    "apple",
    "banana",
    "cherry"
];

arr = arr.concat([
    "dragonfruit",
    "elderberry",
    "fig"
]);

console.log(arr);

Will print

["apple", "banana", "cherry", "dragonfruit", "elderberry", "fig"]

JavaScript - Array push() Method, Javascript array push() is an inbuilt method that can be used to append a number , string, object, Array, or any value to the Array. JavaScript arrays� JavaScript array push() is a function used to incorporate new HTML elements into an array. By default, the push() method will append the new items at the end of the array. After the JavaScript push() function is applied to an array, it will deliver a very specific return value.

Javascript array push: How to Add Item in Javascript Array, Your first snippet: var row = new Array(); var newData = new Array(); for (i = 1; i <= 10 ; i++) { row[0] = i; newData.push(row); }. pushes 10 times� Provided your arrays are not huge (see caveat below), you can use the push() method of the array to which you wish to append values. push() can take multiple parameters so you can use its apply() method to pass the array of values to be pushed as a list of function parameters.

Javascript: push array into array vs. push values , The push method adds a specified element to the end of an array and returns the length of the array. JavaScript Glossary - Lesson 17 of 29. Array .push()� I am looking for a JavaScript array insert method, in the style of: arr.insert(index, item) Preferably in jQuery, but any JavaScript implementation will do at this point.

Array .push() Method ― Scotch.io, JavaScript push() method This method adds new items to the end of the array. This method Duration: 8:58 Posted: Dec 19, 2014 Return value: This method returns the new length of the array after inserting the arguments into the array. Below examples illustrate the JavaScript Array push() method: Example 1: In this example the function push() adds the numbers to the end of the array.

Comments

• array and objects are different in JavaScript karmagination.com/blog/2009/07/29/…
• And this is not JSON. JSON is a markup format that goes inside string data, that happens to look like (and is named after) this Javascript literal syntax.
• Note for future people: The question is wrong. It is not an array, nor JSON. Please read the answers.
• I only have one issue with that, I have some values that are might come in with other charachters, mostly like this.. "BRK.A" so I wont be able to do a json.BRK.A= 32.33;
• You didn't mention anything about "come in" or from where you might be getting the values. So, based on your tags, I assumed vanilla JavaScript.
• In those scenarios, you could do something like... json['BRK.A'] = 3.14159;