CODE EXAMPLE FOR JAVASCRIPT

what is regular expression in javascript

let re = /ol/, 
Characters , ., cX, d, D, f, 
, 
, s, S, 	, v, w, W, , xhh, uhhhh, uhhhhh, []	
Assertions 	^, $, x(?=y), x(?!y), (?<=y)x, (?<!y)x, , B
Groups 		(x), (?:x), (?<Name>x), x|y, [xyz], [^xyz], Number	
Quantifiers *, +, ?, x{n}, x{n,}, x{n,m}
Unicode p{UnicodeProperty}, P{UnicodeProperty}	 property escapes
let defaults = new RegExp('compiled'); 
defaults = { dotAll: false, flags: "", global: false, ignoreCase: false, falselastIndex: 0, multiline: false, source: "abc", sticky: false, unicode: false}