- Use the for-in loop to iterate over non-array objects. Even though we can use for-in loop for array, it is generally not recommended. Instead, use a for loop for looping over an array.
- The properties iterated with for-in loop also includes the properties of the objects higher in the Prototype chain.
- The order in which properties are iterated may not match with the properties that are defined in the object.
For-in loop iterates over properties of an object and it’s prototype chain’s properties.
If we want to display only properties of the “student1” object which belongs to that object only and not on the prototype chain, then we can perform an “if” check with hasOwnProperty() method.
For-in loop with hasOwnProperty check, iterates over properties of the object.