kvdos/jschallenger

JSchallenger is a tool for learning Javascript by solving coding challenges created by Erik Kückelheim. Here is the solution to each challenge.

JSchallenger

Learn Javascript online by solving coding exercises.

• What: JavaScript challenges from JSchallenger.com. It includes my own code in case I got it right as well as challenge's author code.
• Why: Just in case someone is starting, as I am currently, to learn JS and wants to practice.

Big thanks to Erik Kückelheim, the author of JSchallenger.com. It's not easy to find such good exercises for free.

Index

Getting started

Javascript basics

• Check if a number is even
• Multiplication, division, and comparison operators
• Comparison operators, strict equality
• Check if a number is a whole number
• Check whether a string contains another string and concatenate
• Find next higher natural number that is divisble by y
• Round a number to 2 decimal places
• Split a number into its digits
• Find the correct word by incrementing letters in alphabet
• Clear up the chaos behind these strings
• Return the percentage of a number
• How many times does a character occur?
• Return the next higher prime number

Javascript arrays

• Sort an array of strings alphabetically
• Sort an array of numbers in descending order
• Return last n array elements
• Sum up all array elements with values greater than
• Return the average of an array of numbers
• Check if all array elements are equal
• Remove a specific array element
• Create a range of numbers
• Return the longest string from an array of strings
• Merge an arbitrary number of arrays
• Merge two arrays with duplicate values

Javascript dates

• Check if two dates fall on the exact same day
• Check if two dates are equal
• Check if one date is earlier than another
• Add n days to an existing date
• Check if two dates are within 1 hour from each other
• Return the number of days between two dates
• Calculate difference between two dates in hours, minutes, and seconds
• Return the next nearest quarter hour of a date

Javascript objects

• Accessing object properties two
• Accessing object properties one
• Accessing object properties three
• Remove a property from an object
• Swap object keys and values
• Add property to each object in array
• Merge two objects with matching keys
• Extracting information from objects
• Replace empty strings in object with null values

Javascript Sets

• Check if value is present in Set
• Convert a Set to Array
• Get union of two sets
• Creating Javascript Sets
• Delete element from Set
• Add multiple elements to Set
• Get Intersection of two Javascript Sets

jschallenger's Issues

Site error

I've just paid for your 'preium' service and now find that I can't attempt any of the challenges, because a popup error keeps triggering and can't be removed - follow link for screenshot. Hope it gets fixed soon!

'Round a number to 2 decimal places' Challenge

Hi @kvdos

First of all, thanks for the wonderful JS challenge website - https://www.jschallenger.com/ ! :)

When you are free, please have a look of the following issues:

1. The toFixed() method should solve the challenge, however it doesn't.

2. Looks like the link of 'Round a number to 2 decimal places' has an error too.

Many thanks!

Sync across devices

No option to login and sync progress across devices.

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