Practice Exercises

1. Write a function log that takes an Array of Strings and displays them on the console.

2. An application uses an Array as a Stack (LIFO) to keep track of items in a user's shopping history. Every time they browse to an item, you want to addItemToHistory(item). How would you implement this?

3. Write a function buildArray that takes two Numbers, and returns an Array filled with all numbers between the given number: buildArray(5, 10) should return [5, 6, 7, 8, 9, 10]

4. Write a function addDollars that takes an Array of Numbers and uses the array's map() method to create and return a new Array with each element having a $ added to the front: addDollars([1, 2, 3, 4]) should return ['$1', '$2', '$3', '$4']

5. Write a function tidy that takes an Array of Strings and uses the array's map() method to create and return a new Array with each element having all leading/trailing whitespace removed: tidy([' hello', ' world ']) should return ['hello', 'world'].

6. Write a function measure which takes an Array of Strings and uses the array's forEach() method to determine the size of each string in the array, returning the total: measure(['a', 'bc']) should return 3. Bonus: try to rewrite your code using the Array's reduce() method.

7. Write a function whereIsWaldo that takes an Array of Strings and uses the array's forEach() method to create a new Array with only the elements that contain the text "waldo" or "Waldo" somewhere in them: whereIsWaldo(['Jim Waldorf, 'Lynn Waldon', 'Frank Smith']) should return 'Jim Waldorf, 'Lynn Waldon']. Bonus: try to rewrite your code using the Array's filter() method.

8. Write a function checkAges that takes two arguments: an Array of ages (Number); and a cut-off age (Number). Your function should return true if all of the ages in the Array are at least as old as the cut-off age: checkAges([16, 18, 22, 32, 56], 19) should return false and checkAges([16, 18, 22, 32, 56], 6) should return true. Bonus: try to rewrite your code using the Array's every() method.

9. Write a function containsBadWord that takes two arguments: badWords (an Array of words that can't be used), and userName (a String entered by the user). Check to see if any of the words in badWords are contained within userName. Return the badWord that was found, or null if none are found.

10. A String contains a Key/Value pair separated by a ":". Using String methods, how would you extract the two parts? Make sure you also deal with any extra spaces. For example, all of the following should be considered the same: "colour: blue", "colour:blue", "colour : blue", "colour: blue ". Bonus: how could you use a RegExp instead?

11. A String named addresses contains a list of street addresses. Some of the addresses use short forms: "St." instead of "Street" and "Rd" instead of "Road". Using String methods, convert all these short forms to their full versions.

12. Room booking codes must take the following form: room number (1-305) followed by - followed by the month as a number (1-12) followed by the day as a number (1-31). For example, all of the following are valid: "1-1-1", "250-10-3", "66-12-12". Write a RegExp to check whether a room booking code is valid or not, which allows any of the valid forms.

13. Write a function that takes a String and checks whether or not it begins with one of "Mr.", "Mrs.", or "Ms.". Return true if it does, otherwise false. Bonus: try writing your solution using regular String methods and again as a RegExp.

14. Write a function that takes a password String, and validates it according to the following rules: must be between 8-32 characters in length; must contain one Capital Letter; must contain one Number; must contain one Symbol (!@#$%^&*-+{}). Return true if the given password is valid, otherwise false.

15. Write a RegExp for a Canadian Postal Code, for example "M3J 3M6". Allow spaces or no spaces, capitals or lower case.

A Larger Problem Combining Everything:

You are asked to write JavaScript code to process a String which is in the form of a Comma-Separated Values (CSV) formatted data dump of user information. The data might look something like this:

0134134,John Smith,555-567-2341,62 inches
0134135   ,    June    Lee    ,  5554126347 ,        149 cm
0134136,       Kim Thomas       , 5324126347, 138cm`

Write a series of functions to accomplish the following, building a larger program as you go. You can begin with exercise.js:

1. Split the string into an Array of separate rows (i.e., an Array with rows separated by \n). Bonus: how could we deal with data that includes both Unix (\n) and Windows (\r\n) line endings?

2. Each row contains information user info: ID, Name, Phone Number, and Height info all separated by commas. Split each row into an Array with all of its different fields. You need to deal with extra and/or no whitespace between the commas.

3. Get rid of any extra spaces around the Name field

4. Using a RegExp, extract the Area Code from the Phone Number field. All Phone Numbers are in one of two formats: "555-555-5555" or "5555555555".

5. Check if the Height field has "cm" at the end. If it does, strip that out, convert the number to inches, and turn it into a String in the form "xx inches". For example: "152 cm" should become "59 inches".

6. After doing all of the above steps, create a new record with ID, Name, Area Code, Height In Inches and separate them with commas

7. Combine all these processed records into a new CSV formatted string, with rows separated by \n.

A sample solution is provided in solution.js.