After that, you can iterate through the array and retrieve the value of each property using any of the array looping methods, such as forEach(), map(), etc. The object is passed as an argument to Object.keys(). It generates an array whose elements are strings containing the names (keys) of an object's properties. The Object.keys() method was added in ES6 to make looping over objects easier. Loop and Enumerate Object Keys with Object.keys() You can extract keys() and values() individually, or entries(), which are key-value pairs, depending on which properties you'd like to enumerate. Each property in an object has a name (also known as a key) and a corresponding value (also known as a value). Note: An object has properties, which are key-value pairs. Once converted to an array - we have much more flexibility, as well as efficiency in looping through arrays and enumerating them! If you have an object, you cant just iterate it using map(), forEach() or a for.of loop. In this section, we will cover three object static methods for converting object properties to arrays. How to iterate over object properties in JavaScript. Object Static Methods to Loop and Enumerate JavaScript Objects Let’s now consider a better way with a far better syntax which works with fewer technicalities. Secondly, sometimes you may need a little more flexibility, which arrays provide. This is both inefficient, as more looping is done than needs to be, and makes the code less readable. When looping through objects with the for.in loop, you must check if the property belongs to the object using hasOwnProperty(), as shown in the example above. Both for.of and for.in statements iterate over lists the values iterated on are different though, for.in returns a list of keys on the object being iterated. The for.in loop works great, but it has a flaw in that it iterates through properties in the Prototype chain, which has many other properties besides the user's. This results in: Index: 0, firstName: John Suppose we have an object which contains a user details: let user = `) Unfortunately, JavaScript objects are not iterable like arrays or strings, so we can't just loop an object using map(), forEach() or a for…of loop.

In ES6/2015 you can loop through an object like this (using the arrow function): Object.keys(myObj).When writing JavaScript code, you may need to loop through JavaScript objects and enumerate their fields/values.

Javascript for each object