Rediscovering JavaScript

Chapter 5

Here are the solutions to the ​Exercises​, for the Chapter 5, ​Arrow Functions and Functional Style​ chapter.

Exercise 1

For anonymous functions, this and arguments are dynamically scoped and other non-local, non-parameter variables are lexically scoped.

For arrow functions, all non-local, non-parameter variables are lexically scoped.

Exercise 2

Here’s a solution to make the code concise and to use arrow functions:

'use strict';

const success = value => ({ value: value });

const blowup = value => { throw new Error('blowing up with value ' + value); };

const process = function(successFn, errorFn) {
  const value = Math.round(Math.random() * 100, 2);

  return value > 50 ? successFn(value) : errorFn(value); ...