Rediscovering JavaScript

Chapter 11

Here are the solutions to the ​Exercises​, for the Chapter 11, ​Exploring Metaprogramming​ chapter.

Exercise 1

'use strict';

const printProperties = function(obj) {
  for(const property of Object.getOwnPropertyNames(obj)) {
    console.log(`${property} is ${obj[property]}`);
  }
};

printProperties({language: 'JavaScript', typing: 'dynamic'});
printProperties(
  {tool: 'Redux', language: 'JavaScript', purpose: 'transpiler', });

Exercise 2

'use strict';

Number.prototype.percent = function() {
  if(this >= 1) {
    throw new Error('value should be less than 1');
  }

  return `${this * 100}%`;
};

const value1 = 0.35;
const value2 = 0.91;

console.log(value1.percent()); ...