arrow function to call this context

test.js

const materials = [
  'Hydrogen',
  'Helium',
  'Lithium',
  'Beryllium'
];

class Test {

  test = (material) => { // test(material) would show error this.test2 is not a function
  let m = material.length;
  let n = this.test2(m);
  return n;
  }

  test2 = (num) => {
  return num + 2;
  }

  call() {
     console.log(materials.map(this.test));
     // console.log(materials.map(this.test.bind(this))); would work if we want to call method
  }
}


let test = new Test();
test.call();