How to get the length of an object in JavaScript
Last updated: September 27, 2022.
Unlike arrays and strings, JavaScript objects do not have a length
property that you can query.
Properties of objects are not stored and accessible numerically, but according to key value only.
So, to get the length requires a little work.
Getting object length with Object.keys()
The simplest way to do this is to call the keys
method on the in-built and aptly named Object
object, passing in your object. This will return the keys of your object in array format.
This is useful because an array does have a length property. So now all you need to do is query that to get the length of your object:
const myObject = { firstName: "Jerry", lastName: "Seinfeld", occupation: "Comedian", } const res = Object.keys(myObject); console.log(res); // [ "firstName", "lastName", "occupation" ] console.log(res.length); // 3