feat: allow deferring js to specific pages

apps/block_scout_web/assets/js/app.js

@@ -40,7 +40,6 @@ import './lib/market_history_chart'
 import './lib/pending_transactions_toggle'
 import './lib/pretty_json'
 import './lib/reload_button'
-import './lib/smart_contract/code_highlighting'
 import './lib/smart_contract/read_only_functions'
 import './lib/smart_contract/wei_ether_converter'
 import './lib/stop_propagation'

apps/block_scout_web/assets/webpack.config.js

@@ -1,8 +1,35 @@
 const path = require('path');
 const ExtractTextPlugin = require('extract-text-webpack-plugin');
 const CopyWebpackPlugin = require('copy-webpack-plugin');
+const glob = require("glob");
 
-module.exports = {
+const viewScripts = glob.sync('./js/view_specific/**/*.js');
+
+function transpileViewScript(file) {
+  return {
+    entry: file,
+    output: {
+      filename: file.replace('./js/view_specific/', ''),
+      path: path.resolve(__dirname, '../priv/static/js')
+    },
+    module: {
+      rules: [
+        {
+          test: /\.js$/,
+          exclude: /node_modules/,
+          use: {
+            loader: 'babel-loader'
+          }
+        },
+      ]
+    }
+  }
+};
+
+
+
+const appJs =
+  {
     entry: './js/app.js',
     output: {
       filename: 'app.js',
@@ -53,4 +80,6 @@ module.exports = {
       new ExtractTextPlugin('../css/app.css'),
       new CopyWebpackPlugin([{ from: 'static/', to: '../' }])
     ]
-};
+  }
+
+module.exports = viewScripts.map(transpileViewScript).concat(appJs);

apps/block_scout_web/lib/block_scout_web.ex

@@ -50,6 +50,7 @@ defmodule BlockScoutWeb do
         Router.Helpers,
         TabHelpers,
         Tokens.Helpers,
+        Views.ScriptHelpers,
         WeiHelpers
       }
     end

apps/block_scout_web/lib/block_scout_web/templates/layout/app.html.eex

@@ -52,5 +52,6 @@
       }
     </script>
     <script src="<%= static_path(@conn, "/js/app.js") %>"></script>
+    <%= render_existing(@view_module, "scripts.html", assigns) %>
   </body>
 </html>

apps/block_scout_web/lib/block_scout_web/views/address_contract_view.ex

@@ -1,6 +1,10 @@
 defmodule BlockScoutWeb.AddressContractView do
   use BlockScoutWeb, :view
 
+  def render("scripts.html", %{conn: conn}) do
+    render_scripts(conn, "address_contract/code_highlighting.js")
+  end
+
   def format_smart_contract_abi(abi), do: Poison.encode!(abi, pretty: false)
 
   @doc """

apps/block_scout_web/lib/block_scout_web/views/script_helpers.ex

@@ -0,0 +1,28 @@
+defmodule BlockScoutWeb.Views.ScriptHelpers do
+  @moduledoc """
+  Helpers for rendering view specific script tags.
+  """
+
+  import Phoenix.HTML, only: [sigil_E: 2]
+  import BlockScoutWeb.Router.Helpers, only: [static_path: 2]
+
+  def render_scripts(conn, file_names) do
+    conn
+    |> files(file_names)
+    |> Enum.map(fn file ->
+      ~E"""
+        <script src="<%= file %>"> </script>
+      """
+    end)
+  end
+
+  defp files(conn, file_names) do
+    file_names
+    |> List.wrap()
+    |> Enum.map(fn file ->
+      path = "/" <> Path.join("js", file)
+
+      static_path(conn, path)
+    end)
+  end
+end