JavaScript object length

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

JavaScript uses the null value to represent a missing object. Use the strict equality operator ( === ) to check if a value is null . The typeof null returns ‘object’ , which is historical bug in JavaScript that may never be fixed.

JavaScript uses the null value to represent a missing object. Use the strict equality operator ( === ) to check if a value is null . The typeof null returns ‘object’ , which is historical bug in JavaScript that may never be fixed.

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