Typescript Static keyword to Property method and Constructor

Typescript Static keyword to Property method and Constructor

In this blog post, We are going to learn Static keywords with properties, methods, and constructors of a class in typescript.

Static keyword in typescript

static is a keyword that can be applied to the properties and methods of a class in typescript. Static members are accessed using directly using class names.

Typescript static properties and Method example

When you want to call any methods in a class, we will use an object instance for accessing its methods, Static methods will use class names.

In class,

  • Declared static variable and non-static variable
  • Declared static method and non-static method
  • static methods and properties are accessed using class names
  • non-static methods and variables are accessed using an instance of a class ie an object.

It gives a compilation error for the below cases.

  • calling a static method with an object or instance names
  • calling non-static method with class names
class MyClass {
  static staticVariable: number = 0;
  nonStaticVariable: number = 0;
  constructor() {
    console.log("constructor");
  }
  nonStaticMethod() {
    console.log("non static method");
  }
  static staticMethod() {
    console.log("Static method");
  }
}

MyClass.staticMethod(); // This works fine
let myclass1 = new MyClass();
myclass1.nonStaticMethod(); // This works fine

myclass1.staticMethod(); // Compilation Error
MyClass.nonStaticMethod(); // Compilation Error

Static Constructor typescript

when the static keyword is applied to the constructor, the Compiler gives the compilation error ’Static modifier cannot appear on a construct declaration’. In a Typescript, a static keyword does not apply to a class constructor.

class ClassDemo {
  msg: string;
  static constructor(msg: string) {
    this.msg = message;
  }
  hello() {
    return "Hello, " + this.msg;
  }
}
let classDemo = new ClassDemo("world");

typescript static member variable and method Example

We can write a static keyword in a different way using the static method.

Declare static initialization method which will initialize data

class ClassDemo {
  static msg: string;
  constructor() {}
  static construct() {
    this.msg = "static typescript example";
    console.log("construct static method");
  }
}
console.log(ClassDemo.construct);