Regular Expressions 101

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An explanation of your regex will be automatically generated as you type.
Detailed match information will be displayed here automatically.
  • All Tokens
  • Common Tokens
  • General Tokens
  • Anchors
  • Meta Sequences
  • Quantifiers
  • Group Constructs
  • Character Classes
  • Flags/Modifiers
  • Substitution
  • A single character of: a, b or c
    [abc]
  • A character except: a, b or c
    [^abc]
  • A character in the range: a-z
    [a-z]
  • A character not in the range: a-z
    [^a-z]
  • A character in the range: a-z or A-Z
    [a-zA-Z]
  • Any single character
    .
  • Alternate - match either a or b
    a|b
  • Any whitespace character
    \s
  • Any non-whitespace character
    \S
  • Any digit
    \d
  • Any non-digit
    \D
  • Any word character
    \w
  • Any non-word character
    \W
  • Non-capturing group
    (?:...)
  • Capturing group
    (...)
  • Zero or one of a
    a?
  • Zero or more of a
    a*
  • One or more of a
    a+
  • Exactly 3 of a
    a{3}
  • 3 or more of a
    a{3,}
  • Between 3 and 6 of a
    a{3,6}
  • Start of string
    ^
  • End of string
    $
  • A word boundary
    \b
  • Non-word boundary
    \B

Regular Expression
No Match

/
/
gmi

Test String

Substitution

Processing...

Code Generator

Generated Code

const regex = /(\([\w\s].*[\w\s]\)|\(\)) =>/gmi; // Alternative syntax using RegExp constructor // const regex = new RegExp('(\\([\\w\\s].*[\\w\\s]\\)|\\(\\)) =>', 'gmi') const str = `var MODULE = ((my, \$, undefined) => { console.log('EXECUTION FROM LEGACY APP START ===>'); // if private var defined in my module, use that // else create a private var var _private = my._private = my._private || {}, _seal = my._seal = function seal(seal) { if (!seal) { return; } delete my._private; delete my._seal; console.log('SEALED'); }, _unseal = my._unseal = function unseal(unseal) { if (!unseal) { return; } my._seal = _seal; my._private = _private; console.log('UNSEALED'); }; var name = 'Tonny Frank'; _private.name = 'This is a private name: ' + name; _private.reverse = function reverse(str) { return str.split('').reverse().join(''); }; if (\$ === undefined) { console.log('jQuery not defined'); return; } \$(() => { var \$h1 = \$('.card').children('h1'); \$h1.html(_private.reverse(\$h1.html())); }); console.log(my); my.myMethod = () => { console.log('MODULE myMethod Executed'); \$('.name').html('Abhisek ...'); \$('button').click(function (ev) { ev.preventDefault(); console.log(this); \$(this).html('Damn!'); }); }; console.log('EXECUTION FROM LEGACY APP END <==='); return my; })(MODULE || {}, this.jQuery); `; const subst = `function $1`; // The substituted value will be contained in the result variable const result = str.replace(regex, subst); console.log('Substitution result: ', result);

Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions