instanceof is a type Guard, which checks if a value is an instance of a class or a constructor function. It also acts as a Type Guard, helping us the infer the type correctly in the scope
Typescript Union Types
Union Types in Typescript allows a variable to have the ability to store a value of several types. We define union types by using a pipe- (|) to separate each of the possible types. Hence, number | string | boolean is the type of a variable, which can have the value that can be a number, a string, or a boolean.
Typescript String, Boolean, Number & Enum Literal types
TypeScript Literal Types restrict the value of a variable to finite valid values. The latest version of Typescript supports the following Literal Types. String Literal Types,Numeric Literal Types,Boolean Literal Types & Enum Literal Types. This is very useful feature which restrict the possible values, that you can store in a variable
Custom Directive In Angular
In this tutorial, we will show you how to create a Custom Directive in Angular. The Angular directives help us to extend or manipulate the DOM. We can change the appearance, behavior, or layout of a DOM element using the directives. We will build a four directive example s and show you how to Create a custom directive using the
@Directive decorator. We will create both custom attribute directive & custom Structural directive. How to setup selectors. Pass value to it using the @input. How to respond to user inputs, Manipulate the DOM element (Change the Appearance) etc.
Angular track by to improve ngFor Performance
Angular Track by option improves the Performance of the ngFor if the collection has a large no of items and keeps changing. Learn why we need it and how to use it to improve the performance of the ngFor.