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

/
/
g

Test String

Code Generator

Language

Generated Code

const regex = /(?<oldDomain>https?:\/\/(?:registry.yarnpkg.com|registry.npmjs.org|[^\/]+))\/(?<pkgFullName>(?:(?<scopeName>@[\w-]+)(?:\/|%2f))?(?<pkgName>[\w-]+))\/(?:-|download)\/[^#]+-(?<version>[\w\.]+?)\.(?<fileExt>\w+)#(?<hash>\w*)/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?<oldDomain>https?:\\\/\\\/(?:registry.yarnpkg.com|registry.npmjs.org|[^\\\/]+))\\\/(?<pkgFullName>(?:(?<scopeName>@[\\w-]+)(?:\\\/|%2f))?(?<pkgName>[\\w-]+))\\\/(?:-|download)\\\/[^#]+-(?<version>[\\w\\.]+?)\\.(?<fileExt>\\w+)#(?<hash>\\w*)', 'g') const str = `"@22g/utility-types@^8.10.0": version "8.10.0" resolved "https://local.duizhuang.com:4873/@22g%2futility-types/-/utility-types-8.10.0.tgz#b35831f1be7a13359946efa29783541aea63e1a9" integrity sha1-s1gx8b56EzWZRu+il4NUGupj4ak= dependencies: "@types/react" "*" "@babel/helper-annotate-as-pure@^7.0.0": version "7.0.0" resolved "https://registry.npm.taobao.org/@babel/helper-annotate-as-pure/-/@babel/helper-annotate-as-pure-7.0.0.tgz#323d39dd0b50e10c7c06ca7d7638e6864d8c5c32" integrity sha512-3UYcJUj9kvSLbLbUIfQTqzcy5VX7GRZ/CCDrnOaZorFFM01aXp1+GJwuFGV4NDDoAS+mOUyHcO6UD/RfqOks3Q== dependencies: "@babel/types" "^7.0.0" "@babel/helper-builder-binary-assignment-operator-visitor@^7.1.0": version "7.1.0" resolved "https://registry.npm.taobao.org/@babel/helper-builder-binary-assignment-operator-visitor/-/@babel/helper-builder-binary-assignment-operator-visitor-7.1.0.tgz#6b69628dfe4087798e0c4ed98e3d4a6b2fbd2f5f" integrity sha512-qNSR4jrmJ8M1VMM9tibvyRAHXQs2PmaksQF7c1CGJNipfe3D8p+wgNwgso/P2A2r2mdgBWAXljNWR0QRZAMW8w== dependencies: "@babel/helper-explode-assignable-expression" "^7.1.0" "@babel/types" "^7.0.0" "@babel/helper-builder-react-jsx@^7.7.0": version "7.7.0" resolved "https://registry.npm.yarnpkg.org/@babel/helper-builder-react-jsx/download/@babel/helper-builder-react-jsx-7.7.0.tgz#c6b8254d305bacd62beb648e4dea7d3ed79f352d" integrity sha1-xrglTTBbrNYr62SOTep9PtefNS0= dependencies:`; // Reset `lastIndex` if this regex is defined globally // regex.lastIndex = 0; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } // The result can be accessed through the `m`-variable. m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }

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