typescript optional fields code example

Example 1: typescript optional parameters

// Optional Parameters
sayHello(hello?: string) {
	console.log(hello);
}

sayHello(); // Prints 'undefined'

sayHello('world'); // Prints 'world'

Example 2: typescript optional parameters

// Default Parameters
sayHello(hello: string = 'hello') {
  console.log(hello);
}

sayHello(); // Prints 'hello'

sayHello('world'); // Prints 'world'

Example 3: typescript class implements interface

interface Task{
    name: String; //property
    run(arg: any):void; //method
}

class MyTask implements Task{
    name: String;
    constructor(name: String) {
        this.name = name;
    }
	run(arg: any): void {
        console.log(`running: ${this.name}, arg: ${arg}`);
    }
}

let myTask: Task = new MyTask('someTask');
myTask.run("test");