classes.js

// Bind in constructor
class BindInConstructor {
  constructor() {
    this.foo = this.foo.bind(this);
    this.bar = this.bar.bind(this);
  }

  foo() {
    this.bar();
  }

  bar() {
    console.log('Hello');
  }
}

// Bind at call time
class BindAtCallTime {
  foo() {
    this.bar.call(this);
  }

  bar() {
    console.log('Hello');
  }
}


// Use class properties and arrow functions
class ClassPropertiesArrowFunctions {
  foo = () => {
    this.bar();
  };

  bar = () => {
    console.log('Hello');
  };
}