unicorn/no-hex-escape

"\x1B" and "\u001B" are the same character written two ways. \x only reaches the first 256 characters, so a project that uses it ends up with both forms, and a search for one misses the other. \u works for every character.

The rule checks strings, template literals, and regular expressions.

--fix rewrites \x1B to \u001B.

Configure

Off by default. To turn it on:

[lint.rules]
"unicorn/no-hex-escape" = "error" # or "warn"

Examples

Reported:

const notice = "\xA9 2026 Example Inc.";
const reset = `\x1B[0m`;
const controlCharacters = /[\x00-\x1F]/;

Not reported:

const notice = "© 2026 Example Inc.";
const reset = `\u001B[0m`;
const controlCharacters = /[\u0000-\u001F]/;

In String.raw and after an escaped backslash, \x is plain text, not an escape:

const source = String.raw`\x1B\[\d+m`;
const help = "Write \\xA9 for the copyright sign";