Regex in JS

Quiz

"Hello world".search(/le?/g)

3 letters "l"

/el?/g

"Hello world"

part "el"

/el+/g

"Hello world"

part "ell"

"Hello world"

/el??/g

"Hello world"

/el??/g

"Hello world"

part "e"

"Hello world"

/el+?/g

"Hello world"

part "el"

"Hello world"

/el*/g

"Hello world"

part "ell"

"Hello world"

/el*?/g

"Hello world"

letter "e"

"Hello world"

/l{1,2}/g

"Hello world"

parts "ll" and "l"

"Hello world"

/l{1,2}?/g

"Hello world"

3 letters "l"

"Hello world"

/^h/g

"hello hard world"

first letter "h"

"hello hard world"

/d$/

"hello hard world"

last letter "d"

"hello hard world"

/b(?=a2|a3)/g

"a1ba2ba3b"

2 letters "b"

"a1ba2ba3b"

/b(?!a2|a3)/g

"a1ba2ba3b"

last letter "b"

"a1ba2ba3b"

/(?<=a1|a2)b/g

"a1ba2ba3b"

2 letters "d"

"a1ba2ba3b"

/(?<!a1|a2)b/g

"a1ba2ba3b"

last letter "d"

"a1ba2ba3b"

/\bW/g

"Hello World_1"

letter "W"

"Hello World_1"

/\w\d/g

"Hello World_1"

part "_1"

"Hello World_1"

/\Bd/g

"Hello World_1"

/\u{1f933}/g

"💏🤳"

Nothing

"💏🤳"

/\u{1f933}/gu

"💏🤳"

🤳

"💏🤳"

/\p{Script=Latin}/gu

"πüé HelloWorld"

letters "ü", "é", "H", "e", "l", "l", "o", "W", "o", "r", "l", "d"

"πüé HelloWorld"

/\p{Script=Greek}/gu

"πüé HelloWorld"

letter "π"

"πüé HelloWorld"

/\p{White_Space}/gu

"πüé HelloWorld"

/(?<year>[0-9]{4})-(?<month>[0-9]{2})-(?<day>[0-9]{2})/g

"2018-05-22"

Whole date split by groups

"2018-05-22"

/^(?<word>\w+)!\k<word>$/g

"abc!abc"

whole phrase

"abc!abc"

/^(\w+)!\1$/g

"abc!abc"

whole phrase

"abc!abc"

/abc./g

"abc\nabc"

nothing

"abc\nabc"

/abc./s

"abc\nabc"

abc\n

"abc\nabc"

/abc/yg

"abc\nabc"

abc

"abc\nabc"

https://github.com/life777/regex-help