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 January 2020.
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
js
/foo/ig.flags; // "gi"
/^bar/myu.flags; // "muy"
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-get-regexp.prototype.flags |
Browser compatibility
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See also
- Polyfill of
RegExp.prototype.flagsincore-js - es-shims polyfill of
RegExp.prototype.flags - Advanced searching with flags in the Regular expressions guide
RegExp.prototype.source