Enforcing a style rule with a linter that actually fails the build

Background I run a fleet of static sites that publish new content every day, mostly unattended. One of the house style rules is simple: no emoji anywhere in our own copy. That rule is impossible to hold by hand. A single site builds a few hundred HTML files, and emoji can slip into nav icons, button labels, <title> , the RSS feed, or JSON-LD (the JSON-formatted metadata embedded in a page to describe its structure to search engines). Nobody is going to review all of that before every deploy. So I wrote emoji-lint , a check that exits 1 the moment it finds a single emoji . It sits in the pre-deploy gate, which means a failure stops that day's publish. This post is not about the regex. It's about what happens when you put a failing check into real operation: you immediately discover the places where the rule must not apply. How it works The core is unremarkable. A regex holds the emoji code point ranges, the scanner walks each file line by line, and matching lines are reported as JSON. const EMOJI_RE = / [\u {1F000}- \u {1FAFF} \u {2600}- \u {27BF} \u {2B00}- \u {2BFF} \u {1F1E6}- \u {1F1FF} \u {FE0F} \u {200D} \u {2049} \u {203C} \u {2122} \u {2139} ] /u ; \u{FE0F} (variation selector) and \u{200D} (ZWJ) are in there because emoji are not always a single code point. Arrows and similar symbols used in ordinary technical writing are deliberately left out. Catch everything and the check drowns in false positives, at which point people stop reading it. The interesting part came later. Three categories of content look exactly like a violation but must not be treated as one: Verbatim quotes from other people Real proper nouns whose official spelling contains a symbol Passages where the emoji itself is the subject being explained Delete the emoji in any of those and you break something more important than the style rule. One term up front: "masking" here means replacing a range with spaces so the scanner cannot see it. Nothing is deleted from the file. Implementation Scope