Example 1: javascript regex
// \d Any digit character
// \w An alphanumeric character (“word character”)
// \s Any whitespace character (space, tab, newline, and similar)
// \D A character that is not a digit
// \W A nonalphanumeric character
// \S A nonwhitespace character
// . Any character except for newline
// /abc/ A sequence of characters
// /[abc]/ Any character from a set of characters
// /[^abc]/ Any character not in a set of characters
// /[0-9]/ Any character in a range of characters
// /x+/ One or more occurrences of the pattern x
// /x+?/ One or more occurrences, nongreedy
// /x*/ Zero or more occurrences
// /x?/ Zero or one occurrence
// /x{2,4}/ Two to four occurrences
// /(abc)/ A group
// /a|b|c/ Any one of several patterns
// /\d/ Any digit character
// /\w/ An alphanumeric character (“word character”)
// /\s/ Any whitespace character
// /./ Any character except newlines
// /\b/ A word boundary
// /^/ Start of input
// /$/ End of input
Example 2: javascript regex reference
// Javascript Regex Reference
// /abc/ A sequence of characters
// /[abc]/ Any character from a set of characters
// /[^abc]/ Any character not in a set of characters
// /[0-9]/ Any character in a range of characters
// /x+/ One or more occurrences of the pattern x
// /x+?/ One or more occurrences, nongreedy
// /x*/ Zero or more occurrences
// /x?/ Zero or one occurrence
// /x{2,4}/ Two to four occurrences
// /(abc)/ A group
// /a|b|c/ Any one of several patterns
// /\d/ Any digit character
// /\w/ An alphanumeric character (“word character”)
// /\s/ Any whitespace character
// /./ Any character except newlines
// /\b/ A word boundary
// /^/ Start of input
// /$/ End of input
Example 3: using regex in javascript
//Adding '/' around regex
var regex = /\s/g;
//or using RegExp
var regex = new RegExp("\s", "g");
Example 4: what is regular expression in javascript
let re = /ol/,
Characters \, ., \cX, \d, \D, \f, \n, \r, \s, \S, \t, \v, \w, \W, \0, \xhh, \uhhhh, \uhhhhh, [\b]
Assertions ^, $, x(?=y), x(?!y), (?<=y)x, (?<!y)x, \b, \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}
Example 5: js regrex
var s = "Please yes\nmake my day!";
s.match(/yes.*day/);
// Returns null
s.match(/yes[^]*day/);
// Returns 'yes\nmake my day'