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regexUnnecessaryCharacterRanges

Reports character class ranges that span only one or two characters.

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

Reports character class ranges that are unnecessary because they span only one or two characters. A range like [a-a] matches only one character and can be simplified to [a]. A range like [a-b] matches only two adjacent characters and can be written as [ab].

Examples

Section titled “Examples”

Identity Range

Section titled “Identity Range”

A range where the start and end are the same character.

AEconsB0patteAE< =sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#82AAFF;--1:#3B61">B0[a-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:#82AAFF;--1:#3B">61B<0[a] spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#D6DEEB;--1:#40">3

Adjacent Range

Section titled “Adjacent Range”

A range that spans only two consecutive characters.

AEconsB0patteAE< =sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#82AAFF;--1:#3B61">B0[a-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:#82AAFF;--1:#3B">61B0<[ab] spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#D6DEEB;--1:#40">3

RegExp Constructor

Section titled “RegExp Constructor”

The rule also checks regex patterns in RegExp constructor calls.

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[0-<1]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">4E4D<[01] spans="tyle--0:#D9F5DD;--1:#11">1<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 prefer the explicit range syntax for readability or consistency, even when it spans only one or two characters, you might prefer to disable this rule.

Further Reading

Section titled “Further Reading”

Equivalents in Other Linters

Section titled “Equivalents in Other Linters”