isRegExp
function isRegExp(value: unknown): value is RegExp;
Identified by its internal tag rather than by instanceof, so a regular expression from another frame is recognised too.
isX and nonX answer a question and never interrupt control flow; requireX and requireNonX hand the value back or throw. The scheme is explained in Validation conventions.
Parameters
Parameter | Type | Description |
|---|---|---|
|
| The value to check. |
Returns
boolean — true when the value is a regular expression; otherwise false.
In TypeScript the guard narrows value to RegExp inside the branch.
Examples
What passes and what does not
isRegExp(/a/); // => true
isRegExp(new RegExp("a")); // => true
isRegExp("/a/"); // => false
isRegExp({}); // => false
isRegExp(null); // => false
See also
Source
23 September 2026
This documentation was generated with AI (Claude) from the library's source code.