View revealing-module-pattern.js
Use the module pattern to group together similar methods such as database services.
In the example below, the ItemDao (Data Access Object) simulates several functions
that interact with a database.
1. Use modules to encapsulate related functionality.
2. A module pattern at its core is an object literal.
3. When using the module in code, call the functions using the key/value syntax.
For example: itemDao.findOne(1);
4. Wrap the object into a function to create a closure for private variables. Examples
View constructor-pattern.js
1. Use the constructor pattern for object creation using the new keyword.
2. Each instance of the object will have its own reference to this.
3. Link functions to the object using the prototype. This provides a
performance gain because functions aren't copied into each
instance of the object. They are linked to the prototype.
It's better to have one copy of functions around, not multiple copies.
Now, if we can use ES 2015 syntax:
1. Use the class keyword.
View spiral-matrix.js
Draw a spiral matrix.
[ 1, 2, 3, 4]
[12, 13, 14, 5]
[11, 16, 15, 6]
[10, 9, 8, 7]
1. Initialize the multidimensional array.
2. Create counter variables to track positions.
View vowel.js
Create a function to return the total number of vowels in a string.
Use String.prototype.match() to find matches
using a regular expression.
// denotes a regex pattern.
[] instructs match() to find any of these characters.
View pyramid.js
Draw this pyramid.
' # '
' ### '
' ##### '
' ####### '
View steps.js
Create a stair case.
Pseudo Code:
To create a staircase,
Draw a grid to visualize the question.
'# '
'## '
View capitalize.js
Create a function that accepts a string, converts the string to title case, and
returns the result. For title case, the first letter of each word is capitalized.
capitalize('hello world'); //Outputs: 'Hello World'
captialize('the year of the hare'); //Outputs: 'The Year Of The Hare';
Pseudo code:
1. Split the string into array using str.split(' ');
2. Map over the elements in the array. Title case each word using helper function.
View anagram.js
Check to see if two strings are anagrams, where both strings have the same characters in the same quantity.
Only consider characters, not spaces and punctuation. Consider the strings as case insensitive, where capital
letters are the same as lowercase letters.
function anagram(str1, str2) {
//Step 1: Create a data store for each string.
const charMap1 = getCharMap(str1);
const charMap2 = getCharMap(str2);
View chunked-array.js
Given an array and size, create a new array containing chunked elements with the size provided.
For example, given the array ['Alligator', 'Bear', 'Cat', 'Dog', 'Elephant', 'Flamingo', 'Giraffe'] and size 2,
return an array of arrays with 2 elements per array.
[["Alligator", "Black Bear"], ["Cat", "Dog"], ["Elephant", "Flamingo"], ["Giraffe"]]
View fizz-buzz.js
Create a function that console logs the numbers from 1 to n.
- Print "fizz" for multiples of three instead of the number.
- Print "buzz" for multiples of five instead of the number.
- Print "fizzbuzz" for numbers that are multiples of three and five instead of the number.
- Otherwise, print the number itself.
function fizzBuzz(num) {
for (let i = 1; i <= num; i++) {