How to check if a value is a plain object in JavaScript

In this Article we will go through how to check if a value is a plain object only using single line of code in JavaScript. This is a one-line JavaScript code snippet that uses one of the most popular ES6 features => Arrow Function.

Let's define this short function:

const isPlainObject = v => (!!v && typeof v === 'object' && (v.__proto__ === null || v.__proto__ === Object.prototype));

isPlainObject(null);                    // false
isPlainObject('hello world');           // false
isPlainObject([]);                      // false
isPlainObject(Object.create(null));     // false
isPlainObject(function() {});           // false

isPlainObject({});                      // true
isPlainObject({ a: '1', b: '2' });      // true