React: Building Modern Web Applications

The arrow functions

ES6 provides a new way to create functions using the => operator. These functions are called as arrow functions. This new method has a shorter syntax, and the arrow functions are the anonymous functions.

Here is an example that shows how to create an arrow function:

let circleArea = (pi, r) => {
  let area = pi * r * r;
  return area;
}

let result = circleArea(3.14, 3);

console.log(result); //Output "28.26"

Here, circleArea is a variable, referencing to the anonymous arrow function. The previous code is similar to the next code in ES5:

Var circleArea = function(pi, r) {
  var area = pi * r * r;
  return area;
}

var result = circleArea(3.14, 3);

console.log(result); //Output "28.26"

If an arrow function contains just one statement, then ...