Just shipped /modernize-js A slash command that rewrites old JS patterns to modern native equivalents: -> JSON.stringify hack -> structuredClone() -> arr[arr.length - 1] -> arr.at(-1) -> Promise chains -> async/await -> x !== null && x !== undefined -> x ?? fallback -> obj && obj.foo -> obj?.foo -> ...and 13 more Why a slash command and not a skill? Skills need project context. This is just a transformation -- one invocation, done. Install: agentcmds.work/#modernize-js