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

Generated Code

const regex = /(?<=^[\t ]*|[\n;](?:[\t ]*(?:\w+ )?)?)export(?:(?: *(?<type>type) *)|[\t\n ]*)(?<exports>(?:\*(?: +as +\S+)?)|\S+|(?:{[\w\t\n\r "$'*,./-]+?}))[\t ]*from[\t ]*["']\s*(?<specifier>(?:(?<=' *)[^']*[^\s'](?= *'))|(?:(?<=" *)[^"]*[^\s"](?= *"))) *["']/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?<=^[\\t ]*|[\\n;](?:[\\t ]*(?:\\w+ )?)?)export(?:(?: *(?<type>type) *)|[\\t\\n ]*)(?<exports>(?:\\*(?: +as +\\S+)?)|\\S+|(?:{[\\w\\t\\n\\r "$\'*,.\/-]+?}))[\\t ]*from[\\t ]*["\']\\s*(?<specifier>(?:(?<=\' *)[^\']*[^\\s\'](?= *\'))|(?:(?<=" *)[^"]*[^\\s"](?= *"))) *["\']', 'g') const str = `export { default } from './make' export { DEFAULTS, plugin as default, type Options } from './plugin' export type { Config, Result } from './interfaces' export type { default as Options } from './options' export type Foo from '#foo' export type * from "./spaceship" export type * as vehicles from "./spaceship" export * as constants from './constants' export * from './interfaces' export * from './lib' export * from './types' export * from "module-name"; export * as name1 from "module-name";var g;export{name1}from"module-name"; export { name1, /* */ nameN } from "module-name"; export { import1 as name1, import2 as name2, /* */ nameN } from "module-name"; export { default, /* */ } from "module-name"; declare module 'module-name' { export { default } from './make' export { DEFAULTS, plugin as default, type Options } from './plugin' } export { DEFAULTS, plugin as default, type Options } export { defineBuildConfig, type BuildConfig } from "#src" export type { JsonObject, LiteralUnion, Nullable } from '@flex-development/tutils' export { addFive, addFour, addThree, addTwo, squareFive, squareFour, squareThree, squareTwo } from './lib' export * as constants from "./constants" export type { default as Options } export type { default as Options } from "./options" export * from './utils' export interface User {} export abstract class House {} export const { name1, name2: bar } = o; export const [ name1, name2 ] = array; export default async function foo() {} export default foo export default 1 + 1; export type { Config, Result } "export type { default as Statement }" export { name1, /* */ nameN }; export { variable1 as name1, variable2 as name2, /* */ nameN }; export { variable1 as "string name" }; export { name1 as default /*, */ }; export type { CompilerOptionsJson as default }; export { default } export { DEFAULTS, plugin as default, type Options } export type { Config, Result } export type { default as Options } var g;export{name1}; export{name1} export { name1, /* */ nameN } export { import1 as ", import2 as name2, /* */ nameN } export { default, /* */ } // export * from './constants' // export type { default as Statement } /** * * @example * export { default } * export { Config, Result } * export type { default as Options } */ // export * from './constants' //export type { default as Statement } from './statement' /* export type { default as Statement } from './statement' */ /*export type { default as Statement } from './statement' */ /* * @example * export * from './constants' */ /** * @example * export * from './constants' */ /** * * @example * export { default } from './make' * export { Config, Result } from './interfaces' * export type { default as Options } from './options' */ export type { Config, Result } from './interfaces'`; // 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