You have to use bracket notation to push a key value into a JavaScript array.
obj["key3"] = "c"; // dynamic - 'key3' can be a variableNote: use .push() method doesn’t work on an object.
JavaScript array push key value
Simple example code push key and value into an array in JS.
<!DOCTYPE html>
<html>
<body>
<script >
var items = [{
'id1': 1,
'id2': 2,
'id3': 3,
'id4': 4
}];
items[0].id5= 5;
console.log(items)
</script>
</body>
</html>Output:
How to add a new object (key-value pair) to an array in JavaScript?
Answer: Use push() to add elements to the end of an array.
items.push({'id':5});Use unshift() if need to add some element to the beginning of the array i.e:
items.unshift({'id':5});Demo:
items = [{'id': 1}, {'id': 2}, {'id': 3}, {'id': 4}];
items.unshift({'id': 0});
console.log(items);And use splice() in case you want to add an object at a particular index i.e:
items.splice(2, 0, {'id':5});
// ^ Given object will be placed at index 2...Demo:
items = [{'id': 1}, {'id': 2}, {'id': 3}, {'id': 4}];
items.splice(2, 0, {'id': 2.5});
console.log(items);Sometimes .concat() is better than .push() since .concat() returns the new array whereas .push() returns the length of the array.
Therefore, if you are setting a variable equal to the result, use .concat().
items = [{'id': 1}, {'id': 2}, {'id': 3}, {'id': 4}];
newArray = items.push({'id':5})In this case, newArray will return 5 (the length of the array).
newArray = items.concat({'id': 5})Do comment if you have any doubts or suggestions on this Js array topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version