Length of a JavaScript associative array?

You can use the length property from JavaScript to get the length. Let’s create an Associative array −

var details = new Array();
details["Name"] = "John";
details["Age"] = 21;
details["CountryName"] = "US";
details["SubjectName"] = "JavaScript";

Let us now get the length of the associative array −

Example

var details = new Array();
details["Name"] = "John";
details["Age"] = 21;
details["CountryName"] = "US";
details["SubjectName"] = "JavaScript";
console.log("The length=="+Object.keys(details).length);

To run the above program, you need to use the following command −

node fileName.js.

Here, my file name is demo.js.

Output

This will produce the following output −

PS C:\Users\Amit\JavaScript-code> node demo.js
The length==4