Replace Moment.js with a lighter-weight alternative

Moment.js contributes a disproportionately large proportion of our bundle size given its limited actual use in the application. dayjs is an API-compatible replacement that is much smaller, though we would have to confirm it supports the browsers/versions we need. date-fns is another library that, while not API-compatible, has been much-touted recently as a good replacement for Moment.

To evaluate effectiveness at reducing bundle size, you can build a production-like environment with:

$ PROFILE_BUILD=true npm run preview

And then access:

• http://localhost:3000/profile/bundle-analyzer.html
• http://localhost:3000/profile/webpack-visualizer.html

まず PROFILE_BUILD=true npm run preview を実行し、bundle-analyzer.html と webpack-visualizer.html のページを確認します。次に、現在の Moment.js の使用箇所を特定し、dayjs または date-fns が必要なブラウザーをサポートしているか確認します。Moment.js を適切な代替に置き換え、production bundle のサイズが削減されたことを実証できれば完了です。