arrayUnnecessaryLengthChecks

Reports unnecessary array length checks before .some() or .every() calls.

✅ This rule is included in the ts logical presets.

Array#some() returns false for an empty array, so checking array.length !== 0 or array.length > 0 before calling .some() is redundant.

Array#every() returns true for an empty array, so checking array.length === 0 before calling .every() is redundant.

This rule reports these unnecessary length checks.

Examples

❌ Incorre

AEdeclare consB0arr7<2:sp ansty="le--0:#C792EA;--1:#8844">AB0boole53[<];d ivclassNa="meec-li">53arrA72leng5<3 sp ansty="le--0:#C792EA;--1:#8844">AE!<==sp ansty="le--0:#D6DEEB;--1:#403F">5<3 sp ansty="le--0:#F78C6C;--1:#AA09">8<20sp ansty="le--0:#D6DEEB;--1:#403F">5<3 sp ansty="le--0:#C792EA;--1:#8844">AE<&&sp ansty="le--0:#D6DEEB;--1:#403F">53 arrAB0so53(Boolean<);d ivclassNa="meco"><);d>AEdeclare consB0arr7<2:sp ansty="le--0:#C792EA;--1:#8844">AB0boole53[<];d ivclassNa="meec-li">53arrA72leng5<3 sp ansty="le--0:#C792EA;--1:#8844">Asp ansty="le--0:#D6DEEB;--1:#403F">5sp><3 sp ansty="le--0:#F78C6C;--1:#AA09">8<20sp ansty="le--0:#D6DEEB;--1:#403F">5<3 sp ansty="le--0:#C792EA;--1:#8844">AE<&&sp ansty="le--0:#D6DEEB;--1:#403F">53 arrAB0so53(Boolean<);d ivclassNa="meco"><);d>AEdeclare consB0arr7<2:sp ansty="le--0:#C792EA;--1:#8844">AB0boole53[<];d ivclassNa="meec-li">53arrA72leng5<3 sp ansty="le--0:#C792EA;--1:#8844">AE=<==sp ansty="le--0:#D6DEEB;--1:#403F">5<3 sp ansty="le--0:#F78C6C;--1:#AA09">8<20sp ansty="le--0:#D6DEEB;--1:#403F">5<3 sp ansty="le--0:#C792EA;--1:#8844">AE<||sp ansty="le--0:#D6DEEB;--1:#403F">53 arrAB0eve53(Boolean<);d ivclassNa="meco"><);d>

44AEdeclare co61B0a64<4AE spans="tyle--0:#C5E478;--1:#3B">61B0boo3F5<3[] ;divclass="Nameec-">3F53a4<4AE. spans="tyle--0:#82AAFF;--1:#3B">61B03F53(Boole<;di vdivclass="Nameexpressive-">44AEdeclare co61B0a64<4AE spans="tyle--0:#C5E478;--1:#3B">61B0boo3F5<3[] ;divclass="Nameec-">3F53a4<4AE. spans="tyle--0:#82AAFF;--1:#3B">61B0e3F53(Boole<;di vdivclass="Nameexpressive-">44AEdeclare co61B0a64<4AE spans="tyle--0:#C5E478;--1:#3B">61B0boo3F5<3[] ;divclass="Nameec-">3F53a4<4AE. spans="tyle--0:#7FDBCA;--1:#09">6E72le344A30<9820 spans="tyle--0:#D6DEEB;--1:#40">3443F53 a4<4AE. spans="tyle--0:#82AAFF;--1:#3B">61B0e3F53(Boole<;di vdivclass="Nameexpressive-">44AEdeclare co61B0a64<4AE spans="tyle--0:#C5E478;--1:#3B">61B0boo3F5<3[] ;divclass="Nameec-">3F53a4<4AE. spans="tyle--0:#7FDBCA;--1:#09">6E72le344A30<9820 spans="tyle--0:#D6DEEB;--1:#40">3443F53 a4<4AE. spans="tyle--0:#82AAFF;--1:#3B">61B03F53(Boole

Options

This rule is not configurable.

When Not To Use It

If you prefer explicit length checks for documentation purposes, or if your team’s coding standards require them, you may disable this rule.

Further Reading

• MDN: Array.prototype.some()
• MDN: Array.prototype.every()

Equivalents in Other Linters

• ESLint: unicorn/no-useless-length-check
• Oxlint: unicorn/no-useless-length-check