no-control-regex

The characters U+0000 to U+001F are invisible and rarely appear in text you want to match. When one shows up in a regular expression, it's often a typo in an escape, such as \x0C where you meant \xC0.

The rule reports a raw control character and the escapes \x0A, \u000A and, with the u or v flag, \u{A}. It checks regular expression literals and strings passed to RegExp. Named escapes such as \t, \n and \cJ are allowed.

This rule is on by default.

Configure#

On by default as a warning. To turn it off:

[lint.rules]
"no-control-regex" = "off" # or "error"

Examples#

const lineBreak = /\x0A/;

const separator = new RegExp("\x1F");

const lineBreak = /\n/;

const space = /\x20/;

In a string, "\n" is the raw character by the time RegExp sees it. Escape the backslash:

const lineBreak = new RegExp("\n");

const lineBreak = new RegExp("\\n");

When not to use it#

Some formats are built on control characters. Terminal color codes start with \x1B, so a pattern that strips them needs to contain it. Disable the rule for that line:

// eslint-disable-next-line no-control-regex
const colorCodes = /\x1B\[[0-9;]*m/g;