RegExp.prototype.hasIndices
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 hasIndices
accessor property of RegExp
instances returns whether or not the d
flag is used with this regular expression.
Try it
const regex1 = new RegExp("foo", "d");
console.log(regex1.hasIndices);
// Expected output: true
const regex2 = new RegExp("bar");
console.log(regex2.hasIndices);
// Expected output: false
Description
RegExp.prototype.hasIndices
has the value true
if the d
flag was used; otherwise, false
. The d
flag indicates that the result of a regular expression match should contain the start and end indices of the substrings of each capture group. It does not change the regex's interpretation or matching behavior in any way, but only provides additional information in the matching result.
This flag primarily affects the return value of exec()
. If the d
flag is present, the array returned by exec()
has an additional indices
property as described in the exec()
method's return value. Because all other regex-related methods (such as String.prototype.match()
) call exec()
internally, they will also return the indices if the regex has the d
flag.
The set accessor of hasIndices
is undefined
. You cannot change this property directly.
Examples
There's a more detailed usage example at Groups and backreferences > Using groups and match indices.
Using hasIndices
const str1 = "foo bar foo";
const regex1 = /foo/dg;
console.log(regex1.hasIndices); // true
console.log(regex1.exec(str1).indices[0]); // [0, 3]
console.log(regex1.exec(str1).indices[0]); // [8, 11]
const str2 = "foo bar foo";
const regex2 = /foo/;
console.log(regex2.hasIndices); // false
console.log(regex2.exec(str2).indices); // undefined
Specifications
Specification |
---|
ECMAScript® 2025 Language Specification # sec-get-regexp.prototype.hasIndices |
Browser compatibility
Report problems with this compatibility data on GitHubdesktop | mobile | server | ||||||||||||
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hasIndices |
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- Full support
- Full support