What is the difference between constructor and ngOnInit? | Demo | Example

Demo URL

Constructor	ngOninit
A constructor is not the concept of Angular. It is the concept of JavaScript's class.	ngOninit is the second stage of Angular component lifecycle hook whenever is called when angular is done which creating the component.
Constructor is best place to add all dependencies	ngOninit function which guarantees you that the component has already been created.
Constructor is automatically called at the time of creating the object of the class.	Invoked by Angular when component is initialized
Used for Injecting dependencies	Actual business logic performed
we should use constructor() to setup Dependency Injection	is a better place to write "actual work code" that we need to execute as soon as the class is instantiated.