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RegExp.prototype.flags

Baseline Widely available

This feature is well established and works across many devices and browser versions. It's been available across browsers since July 2015.

The flags accessor property of RegExp instances returns the flags of this regular expression.

Try it

// Outputs RegExp flags in alphabetical order

console.log(/foo/gi.flags);
// Expected output: "gi"

console.log(/^bar/muy.flags);
// Expected output: "muy"

Description

RegExp.prototype.flags has a string as its value. Flags in the flags property are sorted alphabetically (from left to right, e.g., "dgimsuvy"). It actually invokes the other flag accessors (hasIndices, global, etc.) one-by-one and concatenates the results.

All built-in functions read the flags property instead of reading individual flag accessors.

The set accessor of flags is undefined. You cannot change this property directly.

Examples

Using flags

/foo/ig.flags; // "gi"
/^bar/myu.flags; // "muy"

Specifications

Specification
ECMAScript® 2027 Language Specification
# sec-get-regexp.prototype.flags

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Opera Safari Chrome Android Firefox for Android Opera Android Safari on iOS Samsung Internet WebView Android WebView on iOS Bun Deno Node.js
flags
49
79
37
39
9
49
37
41
9
5.0
49
9
1.0.0
1.0
6.0.0

See also

  • Polyfill of RegExp.prototype.flags in core-js
  • es-shims polyfill of RegExp.prototype.flags
  • Advanced searching with flags in the Regular expressions guide
  • RegExp.prototype.source

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/flags

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