React Performance: Async Waterfall — Dependency Parallelization. Keywords: better-all dependency parallel. Platform: React/Next.js. Description: Use better-all for operations with partial dependencies to maximize parallelism. Do: Use better-all to start each task at earliest possible moment. Don't: Wait for unrelated data before starting dependent fetch. Good Example: await all({ user() {}, config() {}, profile() { return fetch((await this.$.user).id) } }). Bad Example: const [user, config] = await Promise.all([...]); const profile = await fetchProfile(user.id). Severity: Critical.