regexEscapeBackspaces

Reports escape backspace ([\b]) in character classes.

✅ This rule is included in the ts stylistic and stylisticStrict presets.

Reports the use of \b inside character classes to match the backspace character (U+0008). The word boundary assertion (\b) and the escape backspace ([\b]) look identical, which can cause confusion.

Examples

Escape Backspace in Character Class

Using \b inside a character class matches the backspace character, not a word boundary.

❌ Incorre

AEconsB0patteAE< =sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#82AAFF;--1:#3B61">B<0[sp ansty="le--0:#F78C6C;--1:#AA09">82<\bsp ansty="le--0:#82AAFF;--1:#3B61">B<0]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:#82AAFF;--1:#3B">6<1B0[ spans="tyle--0:#F78C6C;--1:#AA">0982\u<0008 spans="tyle--0:#82AAFF;--1:#3B">6<1B0] spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#D6DEEB;--1:#40">3<8]/>

Mixed Character Class

Even with other characters in the class, \b should be replaced.

❌ Incorre

AEconsB0patteAE< =sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#82AAFF;--1:#3B61">B0<[asp ansty="le--0:#F78C6C;--1:#AA09">82<\bsp ansty="le--0:#82AAFF;--1:#3B61">B<0]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:#82AAFF;--1:#3B">610982\u<0008 spans="tyle--0:#82AAFF;--1:#3B">6<1B0] spans="tyle--0:#D9F5DD;--1:#11">1<111/ spans="tyle--0:#D6DEEB;--1:#40">3<8]/>

RegExp Constructor

The rule also checks regex patterns in RegExp constructor calls.

❌ Incorre

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">482<\\sp ansty="le--0:#ECC48D;--1:#984E">4D1<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">409<82\\ spans="tyle--0:#ECC48D;--1:#98">4E4Du0<008] spans="tyle--0:#D9F5DD;--1:#11">1<111" spans="tyle--0:#D6DEEB;--1:#40">3F<53) ;divclass="Name"><]")>

Word Boundary Is Valid

The word boundary assertion \b outside character classes is valid and not reported.

✅ Corre

AEconsB0patteAE< =sp ansty="le--0:#5CA7E4;--1:#3A68">81<1/sp ansty="le--0:#C792EA;--1:#8844">AE<\bsp ansty="le--0:#5CA7E4;--1:#3A68">8FwoAE<\bsp ansty="le--0:#D9F5DD;--1:#1111">1<1/sp ansty="le--0:#D6DEEB;--1:#403F">5<3;d ivclassNa="meco">

Options

This rule is not configurable.

When Not To Use It

If your codebase has established conventions for using [\b] and all developers working on it understand the differences, you might prefer to disable this rule.

Further Reading

• MDN: Character escape: \b
• MDN: Word boundary assertion: \b

Equivalents in Other Linters

• ESLint: regexp/no-escape-backspace