JavaScript Functions Lab

Introduction

This lab provides an opportunity to practice defining and coding some real-world functions.

Note: Feel free to work in pairs or groups to complete this lab. Also, Google/StackOverflow is a good friend to have around...

Exercise

Setup

Create an index.html.
Create a directory named js.
Create a file named lab-functions.js inside of the js directory.
Use a <script> element in the <head> of index.html to bring the lab-functions.js file into the web page.
The code in lab-functions.js will then execute whenever the page is loaded or refreshed.

Requirements

Define and code the functions below.

Define the functions using the approach as specified (either as a function expression or declaration).

Be sure to number each function with a comment above it.

After each function, call it at least once and console.log the results.

For example, here's the first function, my gift to you:

// 1.
function maxOfTwoNumbers(x, y) {
  return x >= y ? x : y;
}

console.log(maxOfTwoNumbers(3, 9));

// 2.
...

Here are the functions:

(completed above) Define a function, as a function declaration, maxOfTwoNumbers that takes two numbers as arguments and returns the largest of them. If they are the same, return that number. Use the if-then-else construct.
Define a function, as a function expression, maxOfThree that takes three numbers as arguments and returns the largest of them.
Define a function, as a function declaration, isCharAVowel that takes a character as an argument and returns true if it is a vowel, false otherwise.
Define a function, as a function expression, sumArray that takes an array of numbers and returns the sum of those numbers. For example, sumArray([2, 4, 5]); would return 11.
Define a function, as a function declaration, multiplyArray that takes an array of numbers and returns the product those numbers. For example, multiplyArray([2, 4, 5]); would return 40.
Define a function, as a function expression, numArgs that returns the number of arguments passed to the function when called.
Define a function, as a function declaration, reverseString that takes a string, reverses the characters, and returns it. For example, reverseString('rockstar'); would return the string "ratskcor".
Define a function, as a function expression, longestWordLength that takes an array of strings (words) and returns the length of the longest word.
Define a function, as a function declaration, stringsLongerThan that takes an array of strings and a number as arguments; and returns an array of the strings that are longer than the number passed in. For example, stringsLongerThan(['touch', 'me', 'in', 'the', 'morning'], 2); would return ["touch", "the", "morning"].

Bonus - Logic & Conditionals

If you finish the lab and want more to do, do the exercises we didn't get to from the JS Logic & Conditionals lesson this morning:

There is an event with ticket prices that are $50, $65, $85 for standard, premier, and premier plus (for drinks) seating. Seniors, veterans, and students receive a $10 discount while standard patrons receive no discount. Based on hardcoded variables for ticketType and discountType, print out a patrons ticketPrice.
Write this decision tree as a conditional:

(you'll need three variables: parentsVisiting, weather, and money, and the conditional should output what you should do).

For an extra bonus, wrap it up in a function called whatShouldIDoToday()

Complete the following challenges using the ternary operator:

Use conditionals to check if a hardcoded word is "javascript". If it is, console.log "Great language!"
Use conditionals to check if a hardcoded number is odd or even, and then console.log the number is odd or even with the number's value.
Use conditionals to check if a hardcoded number is divisible by 2 or 3 and then console.log that the number is divisible by two or three.
Use conditionals to check if a hardcoded quantity is 1 or greater than one. If the quantity is one or greater console.log either 1 pet or quantity + " pets" respectively.

Additional Resources

MDN Functions

jnewman12/js_functions_lab.md

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