📘RegExp

Regular Expressions

JS ⟩ value ⟩ object ⟩ regex ⟩

Regular expressions are string patterns and used with：

• RegExp ⟩ .exec() , .test().

• String ⟩ match(), matchAll(), replace(), replaceAll(), search(), split().

\w    word character    = [a-zA-Z0-9_]
\s    whitespace        

👉 regular expression cheatsheet

🧨

• By default, regular expressions work on code units, not actual characters❗

• Characters that are composed of two code units (e.g. emojis) behave strangely.

• Enable "/u" flag to support Unicode in regular expressions.

⭐️

JavaScript RegExp objects are stateful when they have the global or sticky flags set (e.g. /foo/g or /foo/y). They store a lastIndex from the previous match.

• test if a string matches a regex: regex.test()

• find index position in the string: str.search()

• only want the first match: regex.exec() or str.match() with /g not set.

• return all matches: str.match()

• obtain capture groups (with /g set): regex.exec() or str.matchAll() ⭐️

🔴

• creating regex

  • creating regex

• regex properties

  • regex flag

  • lastIndex

• pattern matching

  • using regex

  • pattern

• ✨ examples

👥

• str.replace()

• str.replaceWhitespaces()

🛠

• Debuggex - to "see" regex.
• RegExr ⭐️
• Unicode Utilities: Character Properties

📗

• Regular Expression Quick Reference
• JS.info ⟩ Regular expressions
• Eloquent JavaScript ⟩

  • Regular Expressions
  • Parsing .ini file
• RIP Tutorial ⟩ Regular Expressions
• Simple Markdown Parser with JavaScript and Regular Expressions

📘

• JavaScript Guide ⟩ Regular expressions
• References ⟩ Regular expressions
• RegExp