assets:precompile RAILS_ENV=productionを実行するとWARNING in asset size limitという警告が表示される

現在Docker + Rails　環境でアプリを作成しています。

EC2でアプリが動作しないためローカルでproductionモードで動作させています。
具体的には各コマンドの末尾にRAILS_ENV=productionをつけて

DBを作成(rails db:create)
マイグレーションを実行(rails db:migrate)
シードデータを投入
プリコンパイル(rails assets:precompile)

というところまで来ています。

ただ、docker-compose run --rm web rails assets:precompile RAILS_ENV=productionというコマンドを実行したところ
下記のような警告が表示されました。

bash
1WARNING in asset size limit: The following asset(s) exceed the recommended size limit (244 KiB).
2This can impact web performance.
3Assets:
4  js/application-e2fa607a36268bd325e5.js (1.34 MiB)
5  js/tops-3552fb8f1ed147cabba5.js.map.gz (261 KiB)
6  js/application-e2fa607a36268bd325e5.js.gz (493 KiB)
7  js/application-e2fa607a36268bd325e5.js.map.gz (720 KiB)
8  js/application-e2fa607a36268bd325e5.js.br (408 KiB)
9  js/application-e2fa607a36268bd325e5.js.map.br (595 KiB)
10
11WARNING in entrypoint size limit: The following entrypoint(s) combined asset size exceeds the recommended limit (244 KiB). This can impact web performance.
12Entrypoints:
13  application (1.34 MiB)
14      js/application-e2fa607a36268bd325e5.js
15
16
17WARNING in webpack performance recommendations:
18You can limit the size of your bundles by using import() or require.ensure to lazy load some parts of your application.
19For more info visit https://webpack.js.org/guides/code-splitting/
20Child mini-css-extract-plugin node_modules/css-loader/dist/cjs.js??ref--6-1!node_modules/postcss-loader/src/index.js??ref--6-2!node_modules/@ttskch/select2-bootstrap4-theme/dist/select2-bootstrap4.min.css:
21    Entrypoint mini-css-extract-plugin = *
22       2 modules
23Child mini-css-extract-plugin node_modules/css-loader/dist/cjs.js??ref--6-1!node_modules/postcss-loader/src/index.js??ref--6-2!node_modules/select2/dist/css/select2.css:
24    Entrypoint mini-css-extract-plugin = *
25       2 modules

このWARNINGを解消するにはどうすればいいのか調べてみると
[webpack] WARNING in asset size limit、と出たときの対処法
という記事が見つかりましたが、
Rails(webpacker)ではどのようにすればよいのか全くわかりません。
もしわかる方がいらっしゃればご教授いただきますようよろしくお願いいたします(m_ _m)

動作環境

Ruby: 2.5.7
Rails: 6.0.3.5
Docker for Mac: 2.2.0.5

期待する動作

上記のWARNINGログが表示されなくなること
動作が軽くなること

該当しそうなコード

config/webpacker.yml(1/2)

yml
1# Note: You must restart bin/webpack-dev-server for changes to take effect
2
3default: &default
4  source_path: app/javascript
5  source_entry_path: packs
6  public_root_path: public
7  public_output_path: packs
8  cache_path: tmp/cache/webpacker
9  check_yarn_integrity: false
10  webpack_compile_output: true
11
12  # Additional paths webpack should lookup modules
13  # ['app/assets', 'engine/foo/app/assets']
14  resolved_paths: []
15
16  # Reload manifest.json on all requests so we reload latest compiled packs
17  cache_manifest: false
18
19  # Extract and emit a css file
20  extract_css: false
21
22  static_assets_extensions:
23    - .jpg
24    - .jpeg
25    - .png
26    - .gif
27    - .tiff
28    - .ico
29    - .svg
30    - .eot
31    - .otf
32    - .ttf
33    - .woff
34    - .woff2
35
36  extensions:
37    - .mjs
38    - .js
39    - .sass
40    - .scss
41    - .css
42    - .module.sass
43    - .module.scss
44    - .module.css
45    - .png
46    - .svg
47    - .gif
48    - .jpeg
49    - .jpg
50
51development:
52  <<: *default
53  compile: true
54
55  # Verifies that correct packages and versions are installed by inspecting package.json, yarn.lock, and node_modules
56  check_yarn_integrity: true
57
58  # Reference: https://webpack.js.org/configuration/dev-server/
59  dev_server:
60    https: false
61    host: 0.0.0.0
62    port: 3035
63    public: 0.0.0.0:3035
64    hmr: false
65    # Inline should be set to true if using HMR
66    inline: true
67    overlay: true
68    compress: true
69    disable_host_check: true
70    use_local_ip: false
71    quiet: false
72    pretty: false
73    headers:
74      'Access-Control-Allow-Origin': '*'
75    watch_options:
76      ignored: '**/node_modules/**'
77
78
79test:
80  <<: *default
81  compile: true
82
83  # Compile test packs to a separate directory
84  public_output_path: packs-test
85
86production:
87  <<: *default
88
89  # Production depends on precompilation of packs prior to booting for performance.
90  compile: false
91
92  # Extract and emit a css file
93  extract_css: true
94
95  # Cache manifest.json for performance
96  cache_manifest: true
97

config/webpack/production.js

js
1process.env.NODE_ENV = process.env.NODE_ENV || 'production'
2
3const environment = require('./environment')
4
5module.exports = environment.toWebpackConfig()
6