RegEx Examples

regex-examples.js

//  \s    - any whitespace character (including \t, \n and a few others)
//  \S    - any non-whitespace character
//  \w    - any word character (uppercase and lowercase latin alphabet, numbers 0-9, and _)
//  \W    - any non-word character
//  \b    - word boundary (boundaries between \w and \W, matches in-between characters)
//  \B    - non-word boundary (inverse of \b)
//  (?!)  - negative lookahead
//  (?=)  - positive lookahead
//  (?<=) - positive lookbehind
//  (?<!) - negative lookbehind

vconst { log } = console
const s = 'See the parrot. And the goat. And the rooster.'

log(s.match(/\w+?(?=\.)/g))
// Matches []:
// See the [parrot]. And the [goat]. And the [rooster].
// (word before period/full-stop)

log(s.match(/the (?=goat)/g))
// Matches []:
// See the parrot and [the ]goat and the rooster.
// ("the " only before "goat")

log(s.match(/the (?!goat)/g))
// Matches []:
// See [the ]parrot and the goat and [the ]rooster.
// ("the " except before "goat")