freeCodeCamp Algorithm Challenge Template Guide

[camperbot]

Convert the given string to a lowercase sentence with words joined by dashes.

Relevant Links

• String global object
• JS Regex Resources
• JS String Prototype Replace
• JS String Prototype ToLowerCase

Hint: 1

Create a regular expression for all white spaces and underscores.

try to solve the problem now

Hint: 2

You will also have to make everything lowercase.

try to solve the problem now

Hint: 3

The tricky part is getting the regular expression part to work, once you do that then just turn the uppercase to lowercase and replace spaces with underscores using replace() .

try to solve the problem now

Spoiler Alert!

Solution ahead!

Basic Code Solution:

function spinalCase(str) {
  // Create a variable for the white space and underscores.
  var regex = /\s+|_+/g;

  // Replace low-upper case to low-space-uppercase
  str = str.replace(/([a-z])([A-Z])/g, '$1 $2');

  // Replace space and underscore with -
  return str.replace(regex, '-').toLowerCase();
}

// test here
spinalCase('This Is Spinal Tap');

Run Code

Code Explanation:

• regex contains the regular expression /\s+|_+/g , which will select all white spaces and underscores.
• The first replace() puts a space before any encountered uppercase characters in the string str so that the spaces can be replaced by dashes later on.
• While returning the string, another replace() replaces spaces and underscores with dashes using regex .

Intermediate Code Solution:

function spinalCase(str) {
  // Replace low-upper case to low-space-uppercase
  str = str.replace(/([a-z])([A-Z])/g, '$1 $2');
  // Split on whitespace and underscores and join with dash
  return str.toLowerCase().split(/(?:_| )+/) .join('-');
}

// test here
spinalCase('This Is Spinal Tap');

Run Code

Code Explanation:

• Similar to the first solution, the first replace() puts a space before any encountered uppercase characters in the string str so that the spaces can be replaced by dashes later on.
• Instead of using replace() here to replace whitespace and underscores with dashes, the string is split() on the regular expression /(?:_| )+/ and join() -ed on - .

Relevant Links

• JS String Prototype Split
• JS Array Prototype Join

Advanced Code Solution:

function spinalCase(str) {
  // "It's such a fine line between stupid, and clever."
  // --David St. Hubbins

  return str.split(/\s+|_+|(?=[A-Z])/).join('-').toLowerCase()
}

Run Code

Code Explanation:

• Split the string at one of the following conditions ( converted to an array )
  • a whitespace character [ \s ] is encountered
  • underscore character [ _ ] is encountered
  • or is followed by an uppercase letter [ (?=[A-Z]) ]
• Join the array using a hyphen ( - )
• Lowercase the whole resulting string
  • • sign is used so as to avoid multiple spaces.

Relevant Links

• String#split
• RegExp
• Arrray#join
• String#toLowerCase

NOTES FOR CONTRIBUTIONS:

• DO NOT add solutions that are similar to any existing solutions. If you think it is similar but better , then try to merge (or replace) the existing similar solution.
• Add an explanation of your solution.
• Categorize the solution in one of the following categories — Basic , Intermediate and Advanced .
• Please add your username only if you have added any relevant main contents . ( DO NOT remove any existing usernames )

See Wiki Challenge Solution Template for reference.