ダイナミックインポート境界とは？
ダイナミックインポート境界とは、コードが静的な import ではなく非同期の import 呼び出しを使う場所であり、対象モジュールを後で取得できることを示します。bundler はそのような呼び出しをそれぞれ継ぎ目として扱い、インポートされたコード用に別の chunk を出力します。モジュールは、実行が実際にその呼び出しに到達したときにのみダウンロードされます。
なぜ重要か
これらの境界は遅延ロードが起こる場所であり、めったに使われない画面のコードを必要になるまで先送りします。適切に配置すれば、ユーザーフローを壊さずに初期ペイロードを削減できます。
Where this shows up in a real pipeline
A definition is only useful if you can recognise the thing in your own logs. In practice this concept surfaces when a job behaves differently between a local run and a runner, which is where most CI debugging starts.
- Compare a local run against a CI run of the same command before assuming a tool is at fault.
- Runner environments differ in shell, PATH, TTY availability, available memory, and disk. Most CI-only behaviour traces to one of those five.
- Pin tool versions so an environment difference cannot be introduced by an unrelated update.
よくある質問
What is What is a dynamic import Boundary??
A dynamic import boundary is the place where code uses an asynchronous import call instead of a static import, signaling that the target module can be fetched later. Bundlers treat each such call as a seam and emit a separate chunk for the imported code. The module then downloads only when execution actually reaches that call.
Why does What is a dynamic import Boundary? matter in CI/CD?
These boundaries are where lazy loading happens, deferring code for rarely used screens until needed. Placing them well shrinks the initial payload without breaking the user flow.
関連ガイド
What Is a Suspense Boundary?A suspense boundary wraps part of a UI so that while its data or code is loading, a fallback is shown,
What Is commitlint?commitlint is a tool that checks commit messages against a configured convention, rejecting commits that do
What Is Deregistration Delay?Deregistration delay is the time a load balancer keeps serving in-flight requests while draining a target