regexUnusedQuantifiers

Reports quantifiers that match exactly once, making them unnecessary.

✅ This rule is included in the ts logical presets.

Reports quantifiers that match exactly once ({1} or {1,1}), which are unnecessary because the element already matches exactly once by default.

Examples

Exact Match of One

❌ Incorrect

const pattern = /a{1}/;

✅ Correct

const pattern = /a/;

Range of One to One

❌ Incorrect

const pattern = /a{1,1}/;

✅ Correct

const pattern = /a/;

Groups with Useless Quantifiers

❌ Incorrect

const pattern = /(ab){1}/;

✅ Correct

const pattern = /(ab)/;

Character Classes

❌ Incorrect

const pattern = /[a-z]{1}/;

✅ Correct

const pattern = /[a-z]/;

Options

This rule is not configurable.

When Not To Use It

If you intentionally use {1} quantifiers for documentation or consistency purposes, you might want to disable this rule.

Further Reading

• MDN: Quantifier
• MDN: Regular expressions

Equivalents in Other Linters

• ESLint: regexp/no-useless-quantifier