Changes the default for preloading pins

README.md

@@ -198,19 +198,19 @@ Just like with a normal pin, you can also update a pin by running the `pin --dow
 
 ## Preloading pinned modules
 
-To avoid the waterfall effect where the browser has to load one file after another before it can get to the deepest nested import, importmap-rails supports [modulepreload links](https://developers.google.com/web/updates/2017/12/modulepreload). Pinned modules can be preloaded by appending `preload: true` to the pin.
+To avoid the waterfall effect where the browser has to load one file after another before it can get to the deepest nested import, importmap-rails supports [modulepreload links](https://developers.google.com/web/updates/2017/12/modulepreload). All pinned modules are preloaded by default. You can opt-out of preloading by appending `preload: false` to the pin.
 
 Example:
 
 ```ruby
 # config/importmap.rb
-pin "@github/hotkey", to: "https://ga.jspm.io/npm:@github/hotkey@1.4.4/dist/index.js", preload: true
-pin "md5", to: "https://cdn.jsdelivr.net/npm/md5@2.3.0/md5.js"
+pin "@github/hotkey", to: "https://ga.jspm.io/npm:@github/hotkey@1.4.4/dist/index.js"
+pin "md5", to: "https://cdn.jsdelivr.net/npm/md5@2.3.0/md5.js", preload: false
 
 # app/views/layouts/application.html.erb
 <%= javascript_importmap_tags %>
 
-# will include the following link before the importmap is setup:
+# will include only the following link before the importmap is setup:
 <link rel="modulepreload" href="https://ga.jspm.io/npm:@github/hotkey@1.4.4/dist/index.js">
 ...
 ```

lib/importmap/map.rb

@@ -25,12 +25,12 @@ def draw(path = nil, &block)
     self
   end
 
-  def pin(name, to: nil, preload: false)
+  def pin(name, to: nil, preload: true)
     clear_cache
     @packages[name] = MappedFile.new(name: name, path: to || "#{name}.js", preload: preload)
   end
 
-  def pin_all_from(dir, under: nil, to: nil, preload: false)
+  def pin_all_from(dir, under: nil, to: nil, preload: true)
     clear_cache
     @directories[dir] = MappedDir.new(dir: dir, under: under, path: to, preload: preload)
   end

lib/install/config/importmap.rb

@@ -1,3 +1,3 @@
 # Pin npm packages by running ./bin/importmap
 
-pin "application", preload: true
+pin "application"

test/dummy/config/importmap.rb

@@ -1,4 +1,4 @@
 pin_all_from "app/assets/javascripts"
 
-pin "md5", to: "https://cdn.skypack.dev/md5", preload: true
-pin "not_there", to: "nowhere.js"
+pin "md5", to: "https://cdn.skypack.dev/md5"
+pin "not_there", to: "nowhere.js", preload: false

test/fixtures/files/outdated_import_map.rb

@@ -1 +1 @@
-pin "md5", to: "https://cdn.skypack.dev/md5@2.2.0", preload: true
+pin "md5", to: "https://cdn.skypack.dev/md5@2.2.0"

test/fixtures/files/single_quote_outdated_import_map.rb

@@ -1 +1 @@
-pin 'md5', to: 'https://cdn.skypack.dev/md5@2.2.0', preload: true
+pin 'md5', to: 'https://cdn.skypack.dev/md5@2.2.0'

test/fixtures/files/single_quote_outdated_import_map_without_cdn.rb

@@ -1 +1 @@
-pin 'md5', preload: true #@2.2.0
+pin 'md5' #@2.2.0

test/fixtures/files/vulnerable_import_map.rb

@@ -1 +1 @@
-pin "is-svg", to: "https://cdn.skypack.dev/is-svg@3.0.0", preload: true
+pin "is-svg", to: "https://cdn.skypack.dev/is-svg@3.0.0"

test/importmap_test.rb

@@ -4,17 +4,17 @@ class ImportmapTest < ActiveSupport::TestCase
   def setup
     @importmap = Importmap::Map.new.tap do |map|
       map.draw do
-        pin "application"
-        pin "editor", to: "rich_text.js"
-        pin "not_there", to: "nowhere.js"
-        pin "md5", to: "https://cdn.skypack.dev/md5", preload: true
-
-        pin_all_from "app/javascript/controllers", under: "controllers", preload: true
-        pin_all_from "app/javascript/spina/controllers", under: "controllers/spina", preload: true
-        pin_all_from "app/javascript/spina/controllers", under: "controllers/spina", to: "spina/controllers", preload: true
-        pin_all_from "app/javascript/helpers", under: "helpers", preload: true
-        pin_all_from "lib/assets/javascripts", preload: true
-        pin_all_from "app/components", under: "controllers", to: "", preload: true
+        pin "application", preload: false
+        pin "editor", to: "rich_text.js", preload: false
+        pin "not_there", to: "nowhere.js", preload: false
+        pin "md5", to: "https://cdn.skypack.dev/md5"
+
+        pin_all_from "app/javascript/controllers", under: "controllers"
+        pin_all_from "app/javascript/spina/controllers", under: "controllers/spina"
+        pin_all_from "app/javascript/spina/controllers", under: "controllers/spina", to: "spina/controllers"
+        pin_all_from "app/javascript/helpers", under: "helpers"
+        pin_all_from "lib/assets/javascripts"
+        pin_all_from "app/components", under: "controllers", to: ""
       end
     end
   end
@@ -97,7 +97,7 @@ def setup
     set_one = @importmap.preloaded_module_paths(resolver: ApplicationController.helpers, cache_key: "1").to_s
     set_two = @importmap.preloaded_module_paths(resolver: ApplicationController.helpers, cache_key: "2").to_s
 
-    @importmap.pin "something", to: "https://cdn.example.com/somewhere.js", preload: true
+    @importmap.pin "something", to: "https://cdn.example.com/somewhere.js"
 
     assert_not_equal set_one, @importmap.preloaded_module_paths(resolver: ApplicationController.helpers, cache_key: "1").to_s
     assert_not_equal set_two, @importmap.preloaded_module_paths(resolver: ApplicationController.helpers, cache_key: "2").to_s