Get Started With Regex

get-started-with-regex.js

/* 
  GET STARTED WITH REGULAR EXPRESSIONS
  
  1. Main Concepts
  1.1. Capture Groups
  1.2. Quantifiers and Alternation
  1.3. Anchors
  1.4. Character Classes
  1.5. Word Boundary
  1.6. Flags
  1.6.1. Ignore Case
  
  2. Helper Methods
  2.1. String.match()
  2.2. Regex.test()
  2.3. String.replace()
  
  3. Examples
  
*/

/* 
  3.1 Test and extract email patterns from a string

  Valid email patterns:
  
  [email protected]
  [email protected]
  [email protected]
  [email protected]
  [email protected]

  Email regex:
*/

const emailRE = /^[a-z0-9\.\-_]+@{1}[a-z]+.com+\.[\w]{0,2}/;
const emailRE_2 = /^[a-z0-9\.\-_]+@{1}[a-z]+.com(\.\w{2})?$/;


/*
  3.2 Test and extract URL patterns from a string
  
  
  Valid URL patterns
  
  http://www.google.com;
  https://google.com;
  http://google.com?foo=1&bar=1;
  https://www.images.google.com?foo=1&bar=1;
  
  URL regex
*/

const urlRE = /http[s]?:\/\/www.\w*\.\w{3}/;
const urlRE_2 = /(http[s]?:\/\/)(\w*)((?:\.[\w]*)+)((?:[?&]\w+=\w+)*)/;

/*
  3.3. Test and extract phone number patterns from a string
  
  Valid phone number patterns
  
  (85)98765-4321;
  (85)9875-4321;
  85 98765-4321;
  +55 (85) 98765-4321;
  +55 85 98765-4321;
*/

/*
  Phone regex
*/

const phoneRE = /^\(\d{2}\)\w{5}-\d{4}/;
const phoneRE_2 = /^\(\d{2}\)\w{4,5}-\d{4}/;
const phoneRE_3 = /^(\+\d{2}\s)?\(?\d{2}\)?\s?\d{4,5}-\d{4}/;

/*
  4. References
  4.1. https://www.regular-expressions.info/tutorial.html
  4.2. https://regexr.com/
*/