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 = /(?:import(?:\s*){addCssStyle}(?:\s*)from(?:\s*)"(?:[^"]*)")/g; // Alternative syntax using RegExp constructor // const regex = new RegExp('(?:import(?:\\s*){addCssStyle}(?:\\s*)from(?:\\s*)"(?:[^"]*)")', 'g') const str = `import{addCssStyle}from"../addcss/addcss.prod.js";function elog(e){return console.error(e)}function isHTML(e){return e[Symbol.toStringTag].includes("Element")}function appendChild(e,t,n=!1){return isHTML(e)?isHTML(t)?(e.appendChild(t),void(n?loopOf(t):t?.checkParent&&t.checkParent())):elog(\`\${t[Symbol.toStringTag]} is not HTML Element\`):elog(\`\${e[Symbol.toStringTag]} is not HTML Element\`)}function append(e,t,n=!1){if(!isHTML(e))return elog(\`\${e[Symbol.toStringTag]} is not HTML Element\`);if(Array.isArray(t)||(t=[t]),!Array.isArray(t)||!t.length)return elog(\`\${t} is undefined, at least HTML Element or its array\`);if(e.append(...t),n)for(const e of t)e[Symbol.toStringTag].includes("Element")?loopOf(e):console.error(\`\${e[Symbol.toStringTag]} is not HTML Element\`)}function loopOf(e){if(e?.checkParent&&e.checkParent(),0!==e.children.length)for(const t of e.children)t?.checkParent&&t.checkParent(),loopOf(t)}function replaceChildren(e,t,n=!1){if(!isHTML(e))return elog(\`\${e[Symbol.toStringTag]} is not HTML Element\`);if(Array.isArray(t)||(t=[t]),e.replaceChildren(...t),n)for(const e of t)loopOf(e)}function getWidth(e){return Math.ceil(e.getBoundingClientRect().width)}function getHeight(e){return Math.ceil(e.getBoundingClientRect().height)}function getDim(e){const{width:t,height:n}=e?.getBoundingClientRect()??{width:0,height:0};return{width:t,height:n}}function getDimBefore(e,t){const n=e.cloneNode(!0);`; // 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