Macro-based ember version check

.eslintrc.js

@@ -20,6 +20,7 @@ module.exports = {
   rules: {
     '@typescript-eslint/no-explicit-any': 'off',
     '@typescript-eslint/no-empty-function': 'off',
+    'prefer-const': 'off',
   },
 
   overrides: [

README.md

@@ -21,11 +21,15 @@ ember install ember-cached-decorator-polyfill
 
 For addons, pass the `-S` flag.
 
+If you're working in an environment with an explicit Babel config (like a V2
+addon or an app with `ember-cli-babel`'s `{ useBabelConfig: true }`
+mode), see "Explicit Babel Config" below.
+
 ## Compatibility
 
 - Ember.js v3.13 or above
 - Ember CLI v2.13 or above
-- Node.js v10 or above
+- Node.js v14 or above
 
 ## Summary
 
@@ -65,3 +69,18 @@ import 'ember-cached-decorator-polyfill';
 
 Once the upstream types have been updated to reflect RFC 566, this will no
 longer be necessary.
+
+## Explicit Babel Config
+
+In environments where you have an explicit Babel config (like authoring a V2
+addon) you will need to configure this polyfill's babel plugin. Add it to your
+`babel.config.js` like:
+
+```
+{
+  "plugins": [
+    "ember-cached-decorator-polyfill/babel-plugin"
+  ]
+}
+```
+

index.js

@@ -9,7 +9,16 @@ module.exports = {
   included(parent) {
     this._super.included.apply(this, arguments);
 
+    // this adds our babel plugin to our parent package
     this.addBabelPlugin(parent);
+
+    // this ensures our parent package can process macros, since our babel
+    // plugin emits macros
+    if (!this.parent.addons.find((a) => a.name === '@embroider/macros')) {
+      this.addons
+        .find((a) => a.name === '@embroider/macros')
+        .installBabelPlugin(parent);
+    }
   },
 
   addBabelPlugin(parent) {

lib/transpile-modules.ts

@@ -4,65 +4,75 @@ import path from 'path';
 import type * as Babel from '@babel/core';
 import type { types as t } from '@babel/core';
 import type { NodePath } from '@babel/traverse';
+import { ImportUtil } from 'babel-import-util';
+
+interface State {
+  importer: ImportUtil;
+}
 
-/**
- * Based on `babel-plugin-ember-modules-api-polyfill`.
- * @see https://github.com/ember-cli/babel-plugin-ember-modules-api-polyfill/blob/master/src/index.js
- */
 export default function (babel: typeof Babel) {
   const t = babel.types;
 
-  const MODULE = '@glimmer/tracking';
+  const REAL_MODULE = '@glimmer/tracking';
   const IMPORT = 'cached';
-  const REPLACED_MODULE = 'ember-cached-decorator-polyfill';
+  const POLYFILL_MODULE = 'ember-cached-decorator-polyfill';
+  const AVAILABE_AT = '>= 4.1.0-alpha.0';
+
+  // Notice that the only name we introduce into scope here is %%local%%, and we
+  // know that name is safe to use because it's the name the user was already
+  // using in the ImportSpecifier that we're replacing.
+  let loader = babel.template(`
+    let %%local%% = %%macroCondition%%(%%dependencySatisfies%%('ember-source', '${AVAILABE_AT}')) ? 
+      %%importSync%%('${REAL_MODULE}').${IMPORT} : 
+      %%importSync%%('${POLYFILL_MODULE}').${IMPORT};
+  `);
 
   return {
     name: 'ember-cache-decorator-polyfill',
     visitor: {
-      ImportDeclaration(path: NodePath<t.ImportDeclaration>) {
-        const node = path.node;
-        const declarations: t.ImportDeclaration[] = [];
-        const removals: NodePath<t.Node>[] = [];
-        const specifiers = path.get('specifiers');
-        const importPath = node.source.value;
-
-        // Only walk specifiers if this is a module we have a mapping for
-        if (importPath !== MODULE) {
+      Program(path: NodePath<t.Program>, state: State) {
+        state.importer = new ImportUtil(t, path);
+      },
+      ImportDeclaration(path: NodePath<t.ImportDeclaration>, state: State) {
+        if (path.node.source.value !== REAL_MODULE) {
           return;
         }
 
-        // Iterate all the specifiers and attempt to locate their mapping
-        for (const specifierPath of specifiers) {
-          const names = getNames(specifierPath);
-          if (!names) {
-            continue;
-          }
-          if (names.imported !== IMPORT) {
+        for (let specifierPath of path.get('specifiers')) {
+          let names = getNames(specifierPath);
+          if (names?.imported !== IMPORT) {
             continue;
           }
 
-          removals.push(specifierPath);
-
-          declarations.push(
-            t.importDeclaration(
-              [
-                t.importSpecifier(
-                  t.identifier(names.local),
-                  t.identifier(IMPORT)
-                ),
-              ],
-              t.stringLiteral(REPLACED_MODULE)
-            )
+          // using babel-import-util to gain access to these functions ensures
+          // that we will never smash any existing bindings (and we'll reuse
+          // existing imports for these if they exist)
+          let importSync = state.importer.import(
+            path,
+            '@embroider/macros',
+            'importSync'
+          );
+          let macroCondition = state.importer.import(
+            path,
+            '@embroider/macros',
+            'macroCondition'
+          );
+          let dependencySatisfies = state.importer.import(
+            path,
+            '@embroider/macros',
+            'dependencySatisfies'
           );
-        }
 
-        if (removals.length > 0) {
-          if (removals.length === node.specifiers.length) {
-            path.replaceWithMultiple(declarations);
-          } else {
-            removals.forEach((specifierPath) => specifierPath.remove());
-            path.insertAfter(declarations);
-          }
+          specifierPath.remove();
+
+          path.insertAfter(
+            loader({
+              local: t.identifier(names.local),
+              macroCondition,
+              dependencySatisfies,
+              importSync,
+            })
+          );
         }
       },
     },
@@ -81,7 +91,7 @@ function getNames(
   if (specifierPath.isImportDefaultSpecifier()) {
     return { imported: 'default', local: specifierPath.node.local.name };
   } else if (specifierPath.isImportSpecifier()) {
-    const importedNode = specifierPath.node.imported;
+    let importedNode = specifierPath.node.imported;
     if (importedNode.type === 'Identifier') {
       return {
         imported: importedNode.name,

package.json

@@ -14,6 +14,10 @@
     "memoized",
     "memoization"
   ],
+  "exports": {
+    ".": "./index.js",
+    "./babel-plugin": "./lib/transpile-modules.js"
+  },
   "homepage": "https://github.com/ember-polyfills/ember-cached-decorator-polyfill#readme",
   "bugs": {
     "url": "https://github.com/ember-polyfills/ember-cached-decorator-polyfill/issues"
@@ -44,7 +48,9 @@
     "test:ember-compatibility": "ember try:each"
   },
   "dependencies": {
+    "@embroider/macros": "^1.8.3",
     "@glimmer/tracking": "^1.1.2",
+    "babel-import-util": "^1.2.2",
     "ember-cache-primitive-polyfill": "^1.0.1",
     "ember-cli-babel": "^7.26.11",
     "ember-cli-babel-plugin-helpers": "^1.1.1"
@@ -56,7 +62,7 @@
     "@glimmer/component": "^1.1.2",
     "@types/babel__core": "^7.1.19",
     "@types/babel__traverse": "^7.18.1",
-    "@types/ember": "^3.16.0",
+    "@types/ember": "^4.0.1",
     "@types/ember-qunit": "^5.0.1",
     "@types/ember-resolver": "^5.0.9",
     "@types/ember__test-helpers": "^2.8.1",
@@ -112,6 +118,9 @@
     "before": "ember-cli-babel",
     "configPath": "tests/dummy/config"
   },
+  "peerDependencies": {
+    "ember-source": "^3.13.0 | ^4.0.0"
+  },
   "release-it": {
     "plugins": {
       "release-it-lerna-changelog": {

tests/dummy/app/router.ts

@@ -2,7 +2,7 @@ import EmberRouter from '@ember/routing/router';
 import config from 'dummy/config/environment';
 
 export default class Router extends EmberRouter {
-  location = config.locationType;
+  location = config.locationType as 'auto';
   rootURL = config.rootURL;
 }