Class Declaration in Javascript ES6

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    <h1>Hello Plunker!</h1>
    For more information <a href="https://www.tutorialfunda.com/reactjs/javascript-classes/">Class Declaration in Javascript ES6</a>
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        class Employee {
            constructor(name) {
                this.name = name;
            }
            greet() {
                console.log(`Hello ${this.name}!`)
            }
        }
        class Student extends Employee {
            constructor(name, level) {
                super(name);
                this.level = level;
            }
            greet() {
                console.log(`Hello ${this.name}! from ${this.level}`)
            }
        }
        const obj1 = new Employee('Julia');
        const obj2 = new Employee('Max','Primary');
        const obj3 = new Employee('Jane', 'Secondary');
        obj3.greet = () => console.log('Hey I am Extraordinary');

        obj1.greet();
        obj2.greet();
        obj3.greet();

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For More Explanation see: [Class Declaration in Javascript ES6](https://www.tutorialfunda.com/reactjs/javascript-classes/)