The goal of this assignment is to create a JavaScript Library of String functions.
In your repo create a file named: index.js. You'll add code to this file that solves the problems below.
In this assignment you'll create a library of resuable code that works with strings. Strings are a core data type that every application will make use of.
- Make a folder for this project
- Make a folder named
srcthis will hold your developer source code. - Add
src/index.jsadd a file for your developer code - Initialize your directory as an npm project:
npm init -y - Add a
README.md - initialize your folder as a github repo
- Commit your work with git
- Push your work to GitHub
The goal of this first library is to make write utilities that work with Strings. Strings are one of the most common data types that you work with. There are very few programs that don't make use of Strings in one form or another.
JavaScript has a built in String Object/Class that has many methods built into it. These do a lot but often you need to combine these together to do something that has practical use. Your job to write functions that solve the problems below.
Challenge 1
capitalize() - makes the first character of a given string uppercase.
Example: hello world -> Hello world
Strategies:
-
Use
str[0]to get the first character. Then usestr.toUpperCase()to convert that character to uppercase. Next usestr.slice()to get the remainder of the string and combine it with the uppercase first character. -
Use
str.split()to convert the string into an array of characters, upper case the first element of the array withstr.toUpperCase(), and then join the array witharray.join()
Challenge 2
allCaps() - makes all characters uppercase. (this is the same as str.toUpperCase())
Example: foo bar -> FOO BAR
Strategy: Make a new function that uses str.toUpperCase(). You can make an alias with a shorter easier to remember name.
Challenge 3
capitalizeWords() - makes the first character of each word uppercase. Imagine that each word is separated by a space.
Example: do all the things -> Do All The Things
Advanced: capitalizeHeadline() - capitalizes all of the words except the words: the, in, a, an, and, but, for, at, by, from unless one of these words is the first word of the string!
Example: the most foo in bar -> The Most Foo in Bar
Strategies:
- Use
str.split()and split on a' 'space, loop through each of the strings in the array and use yourcapitalize()function on each elemen. You can usearray.map()here and use yourcapitalize()function as the callback. Last, usearray.join()to join all of the elements into a single string.
Challenge 4
removeExtraSpaces() - Removes all spaces from the beginning and end of a String along with any extra spaces in the middle. If more than one space appears in the middle of a string it is replaced by a single space.
Example:
" Hello world! " -> "Hello world!"Advanced: Remove all whitespace characters, this includes return, enter, and tabs along with spaces.
Strategies:
- Use
string.trim()to remove white space from the beginning and ending of a string. Then plit the string into an array withstr.split()(split on the' 'space.) Filter the empty strings and usearray.join()with a ' ' to put them back together.
Challenge 5
kebobCase() - Removes extra spaces and replaces spaces with the hyphen "-", and makes all characters lowercase.
Example: " Hello world " -> "hello-world"
Advanced: Remove special characters from the string. For example: "Hello World!" -> "hello-world" (notice the ! is removed)
Strategies:
- Convert the whole string to lower case with:
string.toLowerCase() - Split the string into an array of characters with:
string.split('') - Filter out the characters you don't want. You want to keep letters, numbers, the space
' ', and the hyphen'-'. One way to approach that is to use the character code. Every character is assigned a number (the character code) for lowercase letters the a through z are codes: 97 to 122. The space " " is character code 32. You can get the character code usingstring.charCodeAt(). To preserve the numbers look for character codes 48 to 57 (0 to 9). You're looking for character codes 32, 48-57, 97-122, and 45. - Use the
removeExtraSpaces()to remove any extra spaces. - Split on the space and join with hyphen.
Challenge 6
snakeCase() - Removes extra space and replaces spaces with an underscore "_", and makes all characters lowercase.
Example: " what the heck " -> "what_the_heck"
Strategies:
- Edit the kebob case function so that it takes the separating character as a parameter. This will allow you to provide the character that replces the space.
Challenge 7
camelCase() - Lowercases the first character of the first word. Then uppercases the first character of all other words, and removes all spaces.
Example: Camel Case -> camelCase
Strategies:
- Use the ideas from
capitalizeWords()function you wrote earlier.str.split()the string on the ' ' to get and array of words. Then loop starting on index 1 (you could usearray.map()) and capitalize each word (use your function for this) thenarray.join()on the '' (empty string).
Challenge 8
shift() this method will take the first character of a string and move to the end of a string:
Example: Hello World -> ello WorldH
Strategies: Use String.slice()
Advanced: Include an optional second parameter that sets the number of characters to shift.
Example: shift('foo bar', 3) -> ' barfoo'
These functions should all take a string as input and return a string as output.
Challenge 9
makeHashTag(str) - This function should convert the given string to a hash tag. A hash tag begins with # and no spaces. Each word in the phrase begins with an uppercase letter.
If the given string has more than three words pick the three longest and make the hash tag from those.
Example:
- input:
"Amazing bongo drums for sale" - output:
['#amazing', '#bongo', '#drums']
Strategies:
- Split the string into an array of words by splitting on the " ". Check the length. Sort by length. Uppercase each of the first three words and add '#' at the beginning.
Challenge 10
isEmpty(str) - Returns true if the given string is empty or contains only whitespace. White space includes: spaces, line returns, and tabs. These characters can be represented with: \n (new line) \r (carrige return), \t (tab).
Example:
- Input:
"Abc def" - Output:
isEmpty("Abc def") // false
// Example - notice source string
// contains tabs, spaces, and returns
const str = `
`;
isEmpty(str) // true Strategies:
- You can use string.trim() to remove spaces at the beginning and end of the string. What's left is either empty characters like returns, enter or tab, or other characters. Loop over the remaining characters, if you find a character that is not
\n,\r, or\treturn false. If you got to the end of the loop return true.
Challenge 11 Adding documentation
Add a readme.md to your GitHub Repo. In this file you will document your library of string functions.
Also include a link to your library on npm. You'll be publishing this npm in class 2.
https://repl.it/@MitchellHudson/String-Study#index.js
- https://youtu.be/jKx45OJSDO4
- https://youtu.be/ZHg0iWJln8E
- https://youtu.be/6MTbBMDWGmA
- https://youtu.be/80y__y2OsHY
- https://youtu.be/sK_a_u0kHvE
- https://youtu.be/3Qnv_hc0rIc
- https://youtu.be/ijB1b-Xet9c
- https://youtu.be/MNDaSp3UUu8
Your completed work is your Github repo and the files in it. Post the link to your work in the progress tracker.
You will use this project for future assignments that will include:
- Publishing to npm
- Writing unit tests
Class 4 - April 8
Mark your progress in the class Progress Tracker and post a link to your GitHub repo in the Repos tab.
Your work will be assessed by a rubric. You can self assess your work by looking at the rubric. Wonder what is expected of your work check the rubric.
| Expectations | Does not meet | Meets | Exceeds |
|---|---|---|---|
| Completion | < 100% of functions written | All functions written | Includes all stretch functions, comments, and documentation |
| Quality | Code is sloppy and/or throws errors | Code is well written with no errors | Considers edge cases |
| Comprehension | Can't explain the code written | Can explain the code | Could write the code again from scratch |
| Work ethic | Few massive commits | Commits outline progress, for example a commit for each challenge as it is completed | Commit messages are clearly describe what was changed |