JeffKatzy / js-advanced-first-class-functions-practice-lab

Functions - forEach, reduce, sort

Objectives

1. Practice using forEach
2. Practice using sort
3. Practice using reduce

Overview

Instructions

Be sure to run the tests to get a feel for the types of problems this lab is asking you to solve.

You'll be writing four functions:

• updateDriverWithKeyAndValue- this function should take in a driver object, a key and a value. The function should not mutate the driver parameter and return a new driver that has an updated value for the key passed int
• destructivelyUpdateDriverWithKeyAndValue - this function should work the same as updateDriverWithKeyAndValue but it should mutate the driver parameter passed in.
• deleteFromDriverByKey - this function should take in a driver object and a key. It should delete the key/value pair for the key that was passed in from the driver object. This should all not actually mutate the driver passed in
• destructivelyDeleteFromDriverByKey - this function should work the same as deleteFromDriverByKey but it should mutate the driver passed in.

Good luck!

HINT: You might find deleteFromDriverByKey to be a bit hard to write non-destructively. Think about how we learned to use Object.assign. What happens if we do

var obj = { foo: 'bar' }

var newObj = Object.assign({}, obj)

newObj // { foo: 'bar' }

delete newObj.foo // true

newObj // {}

obj // { foo: 'bar' }

Remember the workflow:

1. Run learn-test.

2. Read the errors; vocalize what they're asking you to do.

3. Write code; repeat steps 1 and 2 often until a test passes.

4. Repeat as needed for further tests.

5. Run learn submit when finished!

If you open up test/indexTest.js, you will see that in the beforeEach block we initialize our driver array values so that you can focus on what really matters — understanding how to manipulate arrays in JavaScript.

Resources

• MDN: Object

View Javascript Object Lab on Learn.co and start learning to code for free.