pve-eslint/eslint/docs/rules/no-empty-character-class.md
Dominik Csapak eb39fafa4f first commit
includes a (minimal) working wrapper

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
2020-04-06 15:06:03 +02:00

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Markdown

# disallow empty character classes in regular expressions (no-empty-character-class)
Because empty character classes in regular expressions do not match anything, they might be typing mistakes.
```js
var foo = /^abc[]/;
```
## Rule Details
This rule disallows empty character classes in regular expressions.
Examples of **incorrect** code for this rule:
```js
/*eslint no-empty-character-class: "error"*/
/^abc[]/.test("abcdefg"); // false
"abcdefg".match(/^abc[]/); // null
```
Examples of **correct** code for this rule:
```js
/*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:
```js
/*eslint no-empty-character-class: "error"*/
var abcNeverMatches = new RegExp("^abc[]");
```