Add .npmrc & add missing dependencies inside addon

.npmrc

@@ -0,0 +1,9 @@
+# Docs: https://pnpm.io/npmrc
+# https://github.com/emberjs/rfcs/pull/907
+
+# we don't want addons to be bad citizens of the ecosystem
+auto-install-peers=false
+
+# we want true isolation,
+# if a dependency is not declared, we want an error
+resolve-peers-from-workspace-root=false

addon/package.json

@@ -70,6 +70,8 @@
     "@babel/plugin-proposal-class-properties": "^7.18.6",
     "@babel/plugin-proposal-decorators": "^7.20.7",
     "@babel/plugin-transform-typescript": "^7.25.2",
+    "@ember/test-helpers": "^3.0.0",
+    "@ember/test-waiters": "^3.1.0",
     "@embroider/addon-dev": "^3.0.0",
     "@glint/core": "^1.4.0",
     "@glint/environment-ember-loose": "^1.4.0",
@@ -102,6 +104,7 @@
     "@typescript-eslint/eslint-plugin": "^8.3.0",
     "@typescript-eslint/parser": "^8.3.0",
     "babel-plugin-ember-template-compilation": "^2.2.5",
+    "ember-modifier": "^4.2.0",
     "eslint": "^8.57.0",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-ember": "^12.2.0",

addon/src/modifiers/sortable-group.ts

@@ -985,7 +985,7 @@ export default class SortableGroupModifier<T> extends Modifier<SortableGroupModi
     this.element.removeEventListener('focusout', this.focusOut);
   }
 
-  override element!: HTMLElement;
+  element!: HTMLElement;
   didSetup = false;
   named!: NamedArgs<SortableGroupModifierSignature<T>>;
 

addon/src/modifiers/sortable-item.ts

@@ -1020,7 +1020,7 @@ export default class SortableItemModifier<T> extends Modifier<SortableItemModifi
     }
   }
 
-  override element!: HTMLElement;
+  element!: HTMLElement;
   didSetup = false;
   named!: NamedArgs<SortableItemModifierSignature<T>>;
 

docs/package.json

@@ -23,7 +23,7 @@
   "devDependencies": {
     "@babel/core": "^7.20.12",
     "@ember/optional-features": "^2.0.0",
-    "@ember/test-helpers": "^2.6.0",
+    "@ember/test-helpers": "^3.0.0",
     "@ember/test-waiters": "^3.0.1",
     "@embroider/macros": "^1.9.0",
     "@embroider/test-setup": "^1.2.0",
@@ -43,7 +43,7 @@
     "ember-disable-prototype-extensions": "^1.1.3",
     "ember-export-application-global": "^2.0.0",
     "ember-load-initializers": "^2.1.2",
-    "ember-modifier": "^3.2.0",
+    "ember-modifier": "^4.2.0",
     "ember-qunit": "mydea/ember-qunit#fn/ember-auto-import-v2-node-12",
     "ember-resolver": "^8.0.3",
     "ember-source": "^4.2.0",