Scope Lab
Objectives
- Understand the difference between
const
andlet
- Understand how functions determine scope in JavaScript
Introduction
Scuber's drivers are beginning to take some notes down about their customers. Use your knowledge of scope to access and change some of these variables.
Instructions
A word of warning. In this lab, you will practice doing some bad things. For example, we'll ask you to declare variables in global scope, and write functions that break down. We do this, because by testing the limits, and exposing the underbelly of a language you can better understand it, and know what to avoid in the future.
Ok, these are your tasks:
customerName
: Declare a variable in global scope calledcustomerName
using thevar
keyword.upperCaseCustomerName()
: Write a function that accesses that globalcustomerName
variable, and uppercases it.setBestCustomer()
: Write a function that when called, declares a variable calledbestCustomer
in global scope and assigns it to be'not bob'
. (Poor Bob.) Also, poor us, declaring a global variable from inside a function is one of those things we would never want to do normally, but is good for us to explore right now.overwriteBestCustomer()
: See the consequences of declaring a variable in global scope, by writing a new function calledoverwriteBestCustomer()
that changes thatbestCustomer
variable.leastFavoriteCustomer
andchangeLeastFavoriteCustomer()
: Now declare a constant in global scope calledleastFavoriteCustomer
, be sure to assign it some initial value. Ok, now write a function calledchangeLeastFavoriteCustomer()
that attempts to change that constant - notice what JavaScript does when you try to change the constant.
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