ruthmoyano / for-of-4-lyfe

For Of 4 Lyfe

Introduction

This will be an exercise in using function expressions and for of loops.

Most times you iterate through an array, you don't need the index you're currently on, so for of loops are the simpler and nicer-looking choice.

And every function should be declared with a function expression, because it keeps our functions from being reassigned, preventing many a potential bug.

Together, they make a dynamic duo, serving up simpler and safer syntax for solution-slingers!

That one got away from me. Sorry.

Setup

1. Fork and clone.
2. Navigate into the directory.
3. Run jest --watch-all.
4. Code away in main.test.js, NOT main.js. (There isn't one for annoying technical test-related reasons.)
5. Read the tests further down in main.test.js for function usage examples!

Guidelines

• Although we won't be testing for what kind of loop you'll be using, this isn't just an exercise in solving problems. Let's use our new for of loop!
• We WILL be testing for function expressions using const. If you aren't passing that particular test, look up function expressions again, or refer to our example!

Challenge Descriptions

General Looping Problems

• addAll - given an array of numbers, returns the sum of all numbers added together. HINT: this is a reduce problem, reducing a collection of values to one value. In this case, a collection of numbers to one total sum.
• countSpaces - given a string, returns the number of characters that are spaces. HINT: this is a reduce problem, reducing a collection of values to one value.
• countTrues - given an array of booleans, returns the number of true values. HINT: this is a reduce problem, reducing a collection of values to one value.
• makeFriendly - given a paragraph, returns a paragraph where each sentence ends with an exclamation point instead of the period it held before. HINT: this is a string-building problem, and you'll want to mostly append to the string you'll return each character, except when you hit a period.

Maps

A Helpful Reminder

A map:

• returns the same number of items as in the original collection
• with some items transformed

Exercises

• cubeAll - given an array of numbers, returns an array where each number has been cubed (a.k.a. raised to the third power).
• addNoises - given an array of strings, returns an array where each string has appended to it that animal's noise. See tests for examples! HINT: You're definitely going to have to check for each tested-for animal name, but you could use a compound boolean in your if check, or set up an array of your own animals and use .includes, or use a switch statement. Either way, you can look at the tests to see which names should be considered which animals!

Filters

A Helpful Reminder

A filter:

• returns the same number of items or fewer (usually fewer!)
• with NO items transformed

Exercises

• womenOnly - given an array of strings with names and gender, returns an array of only those strings where the gender (the last character in the string) is 'F'. HINT: you can check the character at last index of the string to see if it's an F, but there's also a string method that tells you if a string "ends with" another string. Duck it!
• integersOnly - given an array of numbers, returns an array of only those numbers that are integers. HINT: you can use modulus for htis, it's just SEEMS weird to do so.