sf-wdi-gaia/js-functions-lab

[lab, javascript, functions, scope]

Functions Lab

Introduction

Pair programming encouraged

This lab provides an opportunity to practice implementing some real-world functions. If you pair program, we recommend screen sharing and alternating roles as a "driver" and "navigator" after each step.

Exercise

Requirements

Please write code that implements various functions, following the requirements in the list below:

1. Define a function maxOfTwoNumbers that takes two numbers as arguments and returns the largest of them. Use the if-then-else construct available in Javascript. Do some googling to figure this out if you forget how conditionals work.
2. Define a function maxOfThree that takes three numbers as arguments and returns the largest of them.
3. Write a function isCharacterAVowel that takes a character (i.e. a string of length 1) and returns true if it is a vowel, false otherwise.
4. Define a function sumArray and a function multiplyArray that sums and multiplies (respectively) all the numbers in an array of numbers. For example, sumArray([1,2,3,4]) should return 10, and multiplyArray([1,2,3,4]) should return 24.
5. Write a function that return the number of arguments passed to the function when called.
6. Define a function reverseString that computes the reversal of a string. For example, reverseString("jag testar") should return the string "ratset gaj".
7. Write a function findLongestWord that takes an array of words and returns the length of the longest one.
8. Write a function filterLongWords that takes an array of words and a number i and returns the array of words that are longer than i characters long.

Bonus

1. Add a method reverseString (from question 6) to the object String so that it is possible to call: "General Assembly".reverseString().
2. Write a function that takes a string as argument and returns an object where:

• the keys are the characters that occur in the string
• the values are the number of occurences for each letter, regardless of the case

For example, calling the function with the string "General Assembly" will return:

{
  a: 2,
  b: 1,
  e: 3,
  g: 1,
  l: 2,
  m: 1,
  n: 1,
  r: 1,
  s: 2,
  y: 1
}

Getting started

Open the file functions.js. All the function names are already inside the file, you just need to implement them by adding code inside each one.

Use the Chrome dev tools console to practice executing your code.

Deliverable

Push completed homework up to your fork of this repo.

Additional Resources

• MDN Functions

Self Evaluation

During the previous exercise, rate your progress on a scale of 1-5 (5 being the highest) for the following criteria:

• Persistence: Do you handle frustration well? Do you independently pursue understanding?
• Organization: Do you thoughtfully implement best coding patterns and practices?
• Collaboration: Do you make an effort solve problems and share your ideas with others?
• Communication: Do you clearly convey your thoughts to others in illustrative and clear ways?
• Self-compassion: Do you make productive use of turning failures into learning opportunities?
• Resourcefulness: Do make an effort to compare and contrast new ideas with ones you already know?