Tag: Js typeof Array

The typeof keyword returns “object” for null , so that means a little bit more effort is required. Comparisons can be made: null === null to check strictly for null or null == undefined to check loosely for either null or undefined.

In a JavaScript program, the correct way to check if an object property is undefined is to use the `typeof` operator .26 May 2018

The undefined property indicates that a variable has not been assigned a value, or not declared at all .