Regular expressions – my secret love

1. @stefanjudis Regular expressions – my secret love...
2. ... and things I'm excited about.
3. /^(Hello|Bonjour) dotJS!(.+)$/ Match a string that...
4. /^(Hello|Bonjour) dotJS!(.+)$/ Match a string that starts with...
5. /^(Hello|Bonjour) dotJS!(.+)$/ Match a string that starts with "Hello" or "Bonjour"...
6. /^(Hello|Bonjour) dotJS!(.+)$/ Match a string that starts with "Hello" or "Bonjour" followed by " dotJS!"...
7. /^(Hello|Bonjour) dotJS!(.+)$/ Match a string that starts with "Hello" or "Bonjour" followed by " dotJS!", capture more than one character...
8. /^(Hello|Bonjour) dotJS!(.+)$/ Match a string that starts with "Hello" or "Bonjour" followed by " dotJS!", capture more than one character until the end.
9. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS? How are you?" )
10. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS? How are you?" ) null
11. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS? How are you?" ) null
12. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" )
13. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: "Hello", 2: " How are you?" ]
14. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: "Hello", 2: " How are you doing?" ]
15. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: "Hello", 2: " How are you?" ]
16. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: "Hello", 2: " How are you?" ]
17. /^(Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: "Hello", 2: " How are you?" ]
18. /^(?:Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" )
19. /^(?:Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: " How are you?" ]
20. /^(?:Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: " How are you?" ] (?: ...) – there are non-capturing groups in JavaScript
21. /^(?:Hello|Bonjour) dotJS!(.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: " How are you?" ]
22. /^(?:Hello|Bonjour) dotJS!(?<rest>.+)$/ .exec( "Hello dotJS! How are you?" )
23. /^(?:Hello|Bonjour) dotJS!(?<rest>.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: " How are you?", groups: { rest: " How are you?" } ]
24. /^(?:Hello|Bonjour) dotJS!(?<rest>.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: " How are you?", groups: { rest: " How are you?" } ]
25. /^(?:Hello|Bonjour) dotJS!(?<rest>.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you doing?", 1: " How are you doing?", groups: { rest: " How are you?" } ] (?<name> ...) – there are named capture groups in JavaScript
26. /^(?:Hello|Bonjour) dotJS!(?<rest>.+)$/ .exec( "Hello dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: " How are you doing?", groups: { rest: " How are you?" } ]
27. /^(Bonjour) \1 dotJS!(?<rest>.+)$/ .exec( "Bonjour dotJS! How are you?" )
28. /^(Bonjour) \1 dotJS!(?<rest>.+)$/ .exec( "Bonjour dotJS! How are you?" ) null
29. /^(Bonjour) \1 dotJS!(?<rest>.+)$/ .exec( "Bonjour Bonjour dotJS! How are you?" )
30. /^(Bonjour) \1 dotJS!(?<rest>.+)$/ .exec( "Bonjour Bonjour dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: "Bonjour" 2: " How are you?", groups: { rest: " How are you?" } ]
31. /^(Bonjour) \1 dotJS!(?<rest>.+)$/ .exec( "Bonjour Bonjour dotJS! How are you?" ) [ 0: "Hello dotJS! How are you doing?", 1: "Bonjour" 2: " How are you?", groups: { rest: " How are you?" } ] \1, \2, ... – there are capture group back references in JavaScript
32. /^(Bonjour) \1 dotJS!(?<rest>.+)$/ .exec( "Bonjour Bonjour dotJS! How are you?" ) [ 0: "Hello dotJS! How are you?", 1: "Bonjour" 2: " How are you?", groups: { rest: " How are you?" } ]
33. /^(?:Bonjour) dotJS!(?<rest>.+) \k<rest>$/ .exec( "Bonjour dotJS! How are you?" )
34. /^(?:Bonjour) dotJS!(?<rest>.+) \k<rest>$/ .exec( "Bonjour dotJS! How are you?" ) null
35. /^(?:Bonjour) dotJS!(?<rest>.+) \k<rest>$/ .exec( "Bonjour dotJS! How are you? How are you?" )
36. /^(?:Bonjour) dotJS!(?<rest>.+) \k<rest>$/ .exec( "Bonjour dotJS! How are you? How are you?" ) [ 0: "Bonjour dotJS! How are you? How are you?", 1: " How are you?", groups: { rest: " How are you?" } ]
37. /^(?:Bonjour) dotJS!(?<rest>.+) \k<rest>$/ .exec( "Bonjour dotJS! How are you? How are you?" ) [ 0: "Bonjour dotJS! How are you? How are you?", 1: " How are you?", groups: { rest: " How are you?" } ] \k<name> – there are named capture group back references in JavaScript
38. /^(?:Bonjour) dotJS!(?<rest>.+) \k<rest>$/ .exec( "Bonjour dotJS! How are you? How are you?" )
39. /^(?:Bonjour) dotJS!(?<rest>.+)$/ .exec( "Bonjour dotJS! How are you?" )
40. /^(?:Bonjour) dotJS!(?<rest>.+)$/ .exec( "Bonjour dotJS! How are you?" ) [ 0: "Bonjour dotJS! How are you?", 1: " How are you?", groups: { rest: " How are you?" } ]
41. /^(?:Bonjour) dotJS!(?<rest>.+)$/ .exec( "Bonjour dotJS! How are\nyou?" )
42. /^(?:Bonjour) dotJS!(?<rest>.+)$/ .exec( "Bonjour dotJS! How are\nyou?" ) null
43. /^(?:Bonjour) dotJS!(?<rest>.+)$/s .exec( "Bonjour dotJS! How are\nyou?" )
44. /^(?:Bonjour) dotJS!(?<rest>.+)$/s .exec( "Bonjour dotJS! How are\nyou?" ) [ 0: "Bonjour dotJS! How are↵you?", 1: " How are↵you?", groups: { rest: " How are↵you?" } ]
45. /^(?:Bonjour) dotJS!(?<rest>.+)$/s .exec( "Bonjour dotJS! How are\nyou?" ) [ 0: "Bonjour dotJS! How are↵you?", 1: " How are↵you?", groups: { rest: " How are↵you?" } ] / .../s – the dotall flag really captures every character
46. /^(?:Bonjour) dotJS!(?<rest>.+)$/s .exec( "Bonjour dotJS! How are\nyou?" )
47. /^(?:Bonjour) dotJS!(?<rest>.+)\p{Emoji}$/su .exec( "Bonjour dotJS! How are\nyou?" )
48. /^(?:Bonjour) dotJS!(?<rest>.+)\p{Emoji}$/su .exec( "Bonjour dotJS! How are\nyou?" ) null
49. /^(?:Bonjour) dotJS!(?<rest>.+)\p{Emoji}$/su .exec( "Bonjour dotJS! How are\nyou?" )
50. /^(?:Bonjour) dotJS!(?<rest>.+)\p{Emoji}$/su .exec( "Bonjour dotJS! How are\nyou?" ) [ 0: "Bonjour dotJS! How are↵you?", 1: " How are↵you?", groups: { rest: " How are↵you?" } ]
51. /^(?:Bonjour) dotJS!(?<rest>.+)\p{Math_Symbol}$/su .exec( "Bonjour dotJS! How are\nyou?⁼" ) [ 0: "Bonjour dotJS! How are↵you⁼?", 1: " How are↵you?", groups: { rest: " How are↵you?" } ]
52. /^(?:Bonjour) dotJS!(?<rest>.+)\p{Script=Greek}$/su .exec( "Bonjour dotJS! How are\nyou?μ" ) [ 0: "Bonjour dotJS! How are↵youμ?", 1: " How are↵you?", groups: { rest: " How are↵you?" } ]
53. /^(?:Bonjour) dotJS!(?<rest>.+)\p{Script=Greek}$/su .exec( "Bonjour dotJS! How are\nyou?μ" ) [ 0: "Bonjour dotJS! How are↵youμ?", 1: " How are↵you?", groups: { rest: " How are↵you?" } ] p/{ ...} – unicode property escapes are a thing these days!
54. Other exciting "new" features to check out lookahead and lookbehind assertions
55. Other exciting "new" features to check out lookahead and lookbehind assertions String.prototype.matchAll
56. Other exciting "new" features to check out lookahead and lookbehind assertions String.prototype.matchAll string replacement patterns
57. @stefanjudis www.stefanjudis.com Thanks.