regex101: JavaScript Match Workspace

Positive Lookbehind(?<=^|[\n;](?:[\t ]*(?:\w+ )?)?)

1st Alternative^

^start of string

2nd Alternative[\n;](?:[\t ]*(?:\w+ )?)?

Character Class[\n;]

\na line-feed (newline) character (ASCII 10)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

Non-Capturing Group(?:[\t ]*(?:\w+ )?)?

?repeats the group contents below at most once:

Character Class[\t ]*

*matches any number of characters from the set below:

\ta tab character (ASCII 9)

the literal (32₁₀ / 40₈ / 20₁₆)

Non-Capturing Group(?:\w+ )?

?repeats the group contents below at most once:

\w+any word character, repeated at least once

the literal (32₁₀ / 40₈ / 20₁₆)

exportthe literal text export (case sensitive)

\s*any whitespace character, repeated any number of times

defaultthe literal text default (case sensitive)

Non-Capturing Group(?:\s*(?<modifiers>(?:abstract(?= *class)|async(?=[\S ]))+))?

?repeats the group contents below at most once:

\s*any whitespace character, repeated any number of times

Group modifiers(?<modifiers>(?:abstract(?= *class)|async(?=[\S ]))+)

Non-Capturing Group(?:abstract(?= *class)|async(?=[\S ]))+

+repeats the group contents below at least once:

1st Alternativeabstract(?= *class)

abstractthe literal text abstract (case sensitive)

Positive Lookahead(?= *class)

*the literal (32₁₀ / 40₈ / 20₁₆) , repeated any number of times

classthe literal text class (case sensitive)

2nd Alternativeasync(?=[\S ])

asyncthe literal text async (case sensitive)

Positive Lookahead(?=[\S ])

Character Class[\S ]

\Sany non-whitespace character

the literal (32₁₀ / 40₈ / 20₁₆)

Non-Capturing Group(?:\s*(?<kind>class|const +enum|enum|function\*?(?=[ (])|interface|namespace|type(?! *\{)))?

?repeats the group contents below at most once:

\s*any whitespace character, repeated any number of times

Group kind(?<kind>class|const +enum|enum|function\*?(?=[ (])|interface|namespace|type(?! *\{))

1st Alternativeclass

classthe literal text class (case sensitive)

2nd Alternativeconst +enum

constthe literal text const (case sensitive)

+the literal (32₁₀ / 40₈ / 20₁₆) , repeated at least once

enumthe literal text enum (case sensitive)

3rd Alternativeenum

enumthe literal text enum (case sensitive)

4th Alternativefunction\*?(?=[ (])

functionthe literal text function (case sensitive)

\*?optionally matches the literal * (42₁₀ / 52₈ / 2A₁₆)

Positive Lookahead(?=[ (])

Character Class[ (]

the literal (32₁₀ / 40₈ / 20₁₆)

(the literal ( (40₁₀ / 50₈ / 28₁₆)

5th Alternativeinterface

interfacethe literal text interface (case sensitive)

6th Alternativenamespace

namespacethe literal text namespace (case sensitive)

7th Alternativetype(?! *\{)

Non-Capturing Group(?:\s*(?<exports>[$_\p{ID_Start}][$\u200C\u200D\p{ID_Continue}]*)(?=(?:\s*[\n({;])|(?:\s*=\s*\{)|$))?

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

u modifier: unicode. Enables Unicode-aware matching and escape syntax

26 tokens

Regular Expression

(?<=^|[\n;](?:[\t ]*(?:\w+ )?)?)export\s*default(?:\s*(?<modifiers>(?:abstract(?= *class)|async(?=[\S ]))+))?(?:\s*(?<kind>class|const +enum|enum|function\*?(?=[ (])|interface|namespace|type(?! *\{)))?(?:\s*(?<exports>[$_\p{ID_Start}][$\u200C\u200D\p{ID_Continue}]*)(?=(?:\s*[\n({;])|(?:\s*=\s*\{)|$))?

New

export default function () { /* … */ }
export default async function() { /* … */ }
export default function* () { /* … */ }
export default async function* () { /* … */ }
export default class { /* … */ }

export default async function functionName() { /* … */ }
export default function functionName() { /* … */ }
export default function* generatorName() { /* … */ }
export default async function* generatorNameAsync() { /* … */ }
export default class ClassName { /* … */ }
export default abstract class ClassName { /* … */ }
export default type Options = {}

export default async () => {}
export default async arg => {}
export default () => {}
export default arg => {}
export default (arg) => {}

export default foo
export default foo;export default foo
export default 1 + 1;
export default {};

declare module 'module-name' {
  export default class ClassName { /* … */ }
}

"export default type Options = {}"

/*export default foo */

/* export default foo */

//export default foo

// export default foo

/**
 * Resolvable file extensions.
 *
 * @example
 *	 export default async function read () {}
 */

export default type Options = {}

Regular Expressions 101

Regular Expression

Extraction