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

/
/
gu

Test String

Code Generator

Generated Code

$re = '/(?<=^|[\n;](?:[\t ]*(?:\w+ )?)?)export\s*(?<modifiers>(?:\s*declare|\s*abstract|\s*async)+)?\s*(?<declaration>class|const +enum|const|enum|function\*?|interface|let|namespace|type(?! *\{)|var)\s+(?<exports>(?:[$_\p{ID_Start}][$\u200C\u200D\p{ID_Continue}]*(?=[\s=:;/({])(?!.*?,))|(?:[\w\t\n\r .,:$\'"=-]+)|(?:[{[][\w\t\n\r .,:$\'"-]+[}\]]))(?:\s*=\s*[$_\p{ID_Start}][$\u200C\u200D\p{ID_Continue}]*)?/u'; $str = 'export const CJS_SYNTAX_REGEX: RegExp = /pattern/gm;export const IGNORE_PATTERNS: string[] = []; export declare const RESOLVE_EXTENSIONS: string[] export enum Snack{} export const enum Snack {} export interface User {} export class House {} export declare abstract class House extends Building {} export abstract class House {} export async function run() {} export async function* run() {} export function foo() {} export function* foo() {} export const $foo = 42 export const $foo= 42 export namespace Foo {} export type Foo = \'foo\' export let name1, name2/*, … */; // also var export const name1 = 1, name2 = 2/*, … */; // also var, let export function functionName() { /* … */ } export class ClassName { /* … */ } export function* generatorFunctionName() { /* … */ } export const { name1, name2: bar } = o; export const [ name1, name2 ] = array; declare module \'module-name\' { export declare abstract class Building {} export declare class House extends Building {} } "export const $foo = 42" export default async function functionName() { /* … */ } export default function functionName() { /* … */ } export default function* generatorName() { /* … */ } export default async function* generatorNameAsync() { /* … */ } export default class ClassName { /* … */ } export default abstract class ClassName { /* … */ } export default function () { /* … */ } export default async function () { /* … */ } export default function* () { /* … */ } export default async function* () { /* … */ } export default class { /* … */ } export default async () => {} export default async arg => {} export default () => {} export default arg => {} export default (arg) => {} export default foo export default foo; export default 1 + 1; // export const CJS_SYNTAX_REGEX /** * Resolvable file extensions. * * @example * export const CJS_SYNTAX_REGEX */ export type Foo = \'foo\''; preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0); // Print the entire match result var_dump($matches);

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 PHP, please visit: http://php.net/manual/en/ref.pcre.php