no-nonoctal-decimal-escape

"\8" and "\9" are the same as "8" and "9". The backslash does nothing, so it's either left over or the author meant a real backslash, "\\8".

In strict mode, which includes every ES module, these escapes are a syntax error. The rule matters for scripts and CommonJS files, where they still parse.

The report comes with two suggestions: remove the backslash, which keeps the string's value, or double it. --fix-suggestions applies the first.

This rule is on by default.

Configure

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

[lint.rules]
"no-nonoctal-decimal-escape" = "off" # or "error"

Examples

Reported, in a file named release.cjs:

const version = "v\8.0";

Not reported:

const version = "v8.0";
const folder = "releases\\8.0";