Font Awesome 5をインストール
コマンドで下記を実行
yarn add @fortawesome/fontawesome-free
成功すると、下記のような表示
yarn add v1.22.4
[1/4] 🔍 Resolving packages...
[2/4] 🚚 Fetching packages...
[3/4] 🔗 Linking dependencies...
warning " > webpack-dev-server@3.11.0" has unmet peer dependency "webpack@^4.0.0 || ^5.0.0".
warning "webpack-dev-server > webpack-dev-middleware@3.7.2" has unmet peer dependency "webpack@^4.0.0".
[4/4] 🔨 Building fresh packages...
success Saved lockfile.
warning Your current version of Yarn is out of date. The latest version is "1.22.5", while you're on "1.22.4".
info To upgrade, run the following command:
$ brew upgrade yarn
success Saved 1 new dependency.
info Direct dependencies
└─ @fortawesome/fontawesome-free@5.15.1
info All dependencies
└─ @fortawesome/fontawesome-free@5.15.1
✨ Done in 4.50s.
application.jsにimportする
app/javascript/packs/application.js
に下記を追加
import '@fortawesome/fontawesome-free/js/all'
フォントオーサムからアイコンを選んで記述
https://fontawesome.com/icons?d=gallery
<i class="fas fa-plus fa-fw"></i>
これで終わりです。