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regexEmptyGroups

Reports empty groups in regular expressions.

✅ This rule is included in the ts logical and logicalStrict presets.

Reports empty capturing and non-capturing groups in regular expressions. Empty groups like () or (?:) match the empty string and have no meaningful effect on the regex pattern. This rule reports those empty groups.

Examples

Section titled “Examples”

Empty Capturing Group

Section titled “Empty Capturing Group”
AEconsB0patteAE <= sp ansty="le--0:#D9F5DD;--1:#1111">1<1/sp ansty="le--0:#5CA7E4;--1:#3A68">8F<()sp ansty="le--0:#D9F5DD;--1:#1111">1<1/sp ansty="le--0:#D6DEEB;--1:#403F">5<3;d ivclassNa="meco">
44AEco61B0pat446<88F spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#5CA7E4;--1:#3A">6881<111/ spans="tyle--0:#D6DEEB;--1:#40">3

Empty Non-Capturing Group

Section titled “Empty Non-Capturing Group”
AEconsB0patteAE< =sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#5CA7E4;--1:#3A68">8F(?<:)sp ansty="le--0:#D9F5DD;--1:#1111">1<1/sp ansty="le--0:#D6DEEB;--1:#403F">5<3;d ivclassNa="meco">
44AEco61B0pat446<88F spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#5CA7E4;--1:#3A">688F(1<111/ spans="tyle--0:#D6DEEB;--1:#40">3

Empty Group with Empty Alternatives

Section titled “Empty Group with Empty Alternatives”
AEconsB0patteAE< =sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#5CA7E4;--1:#3A68">87<2|sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#D6DEEB;--1:#403F">5<3;d ivclassNa="meco">
44AEco61B0pat446<88F spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#5CA7E4;--1:#3A">68<8F(a spans="tyle--0:#7FDBCA;--1:#09">66<88F) spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#D6DEEB;--1:#40">3<|)/>

RegExp Constructor

Section titled “RegExp Constructor”
AEconsB0patteAE <= sp ansty="le--0:#7FDBCA;--1:#096E">72nAB0RegE5<3(sp ansty="le--0:#D9F5DD;--1:#1111">1<1"sp ansty="le--0:#ECC48D;--1:#984E">4D<()sp ansty="le--0:#D9F5DD;--1:#1111">1<1"sp ansty="le--0:#D6DEEB;--1:#403F">53<);d ivclassNa="meco"><);d>
44AEco61B0pat44A6E7<2new spans="tyle--0:#C792EA;--1:#88">4<4AE spans="tyle--0:#82AAFF;--1:#3B">61B0Re31<111" spans="tyle--0:#ECC48D;--1:#98">4E41<111" spans="tyle--0:#D6DEEB;--1:#40">3F<53) ;divclass="Name"><)")>

Options

Section titled “Options”

This rule is not configurable.

When Not To Use It

Section titled “When Not To Use It”

If you are intentionally using empty groups for some specific purpose in generated or legacy code, such as for stylistic separations, you might prefer to disable this rule. You might consider using Flint disable comments and/or configuration file disables for those specific situations instead of completely disabling this rule.

Further Reading

Section titled “Further Reading”

Equivalents in Other Linters

Section titled “Equivalents in Other Linters”