ESLint
disallow empty character classes in regular expressions (no-empty-character-class)
The "extends": "eslint:recommended" property in a configuration file enables this rule.
Because empty character classes in regular expressions do not match anything, they might be typing mistakes.
var foo = /^abc[]/;
Rule Details
This rule disallows empty character classes in regular expressions.
Examples of incorrect code for this rule:
/*eslint no-empty-character-class: "error"*/
/^abc[]/.test("abcdefg"); // false
"abcdefg".match(/^abc[]/); // null
Examples of correct code for this rule:
/*eslint no-empty-character-class: "error"*/
/^abc/.test("abcdefg"); // true
"abcdefg".match(/^abc/); // ["abc"]
/^abc[a-z]/.test("abcdefg"); // true
"abcdefg".match(/^abc[a-z]/); // ["abcd"]
Known Limitations
This rule does not report empty character classes in the string argument of calls to the RegExp constructor.
Example of a false negative when this rule reports correct code:
/*eslint no-empty-character-class: "error"*/
var abcNeverMatches = new RegExp("^abc[]");
Version
This rule was introduced in ESLint 0.22.0.
