feat: add apexContinuation transformer

packages/@lwc/jest-transformer/src/index.js

@@ -14,6 +14,7 @@ const engineVersion = require('@lwc/engine/package.json').version;
 const compilerVersion = require('@lwc/compiler/package.json').version;
 const { waitForPromise } = require('./utils');
 const apexScopedImport = require('./transforms/apex-scoped-import');
+const apexContinuationScopedImport = require('./transforms/apex-continuation-scoped-import');
 const i18nScopedImport = require('./transforms/i18n-scoped-import');
 const labelScopedImport = require('./transforms/label-scoped-import');
 const resourceScopedImport = require('./transforms/resource-scoped-import');
@@ -29,6 +30,7 @@ const BABEL_CONFIG = {
     "plugins": [
         babelCommonJs,
         apexScopedImport,
+        apexContinuationScopedImport,
         i18nScopedImport,
         labelScopedImport,
         contentAssetUrlScopedImport,

packages/@lwc/jest-transformer/src/transforms/__tests__/apex-continuation-scoped-import.test.js

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2018, salesforce.com, inc.
+ * All rights reserved.
+ * SPDX-License-Identifier: MIT
+ * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
+ */
+const test = require('./utils/test-transform').test(
+    require('../apex-continuation-scoped-import')
+);
+
+describe('@salesforce/apexContinuation import', () => {
+    test('does default transformation', `
+        import myMethod from '@salesforce/apexContinuation/FooController.fooMethod';
+    `, `
+        let myMethod;
+
+        try {
+          myMethod = require("@salesforce/apexContinuation/FooController.fooMethod").default;
+        } catch (e) {
+          global.__lwcJestMock_myMethod = global.__lwcJestMock_myMethod || function () {
+            return Promise.resolve();
+          };
+
+          myMethod = global.__lwcJestMock_myMethod;
+        }
+    `);
+
+    test('allows non-@salesforce/apexContinuation named imports', `
+        import { otherNamed } from './something-valid';
+        import myMethod from '@salesforce/apexContinuation/FooController.fooMethod';
+    `, `
+        import { otherNamed } from './something-valid';
+        let myMethod;
+
+        try {
+          myMethod = require("@salesforce/apexContinuation/FooController.fooMethod").default;
+        } catch (e) {
+          global.__lwcJestMock_myMethod = global.__lwcJestMock_myMethod || function () {
+            return Promise.resolve();
+          };
+
+          myMethod = global.__lwcJestMock_myMethod;
+        }
+    `);
+});

packages/@lwc/jest-transformer/src/transforms/apex-continuation-scoped-import.js

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2018, salesforce.com, inc.
+ * All rights reserved.
+ * SPDX-License-Identifier: MIT
+ * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/MIT
+ */
+const babelTemplate = require('@babel/template').default;
+const { getImportInfo } = require('./utils');
+
+const APEX_CONTINUATION_IMPORT_IDENTIFIER = '@salesforce/apexContinuation';
+
+/*
+ * Apex imports can be used as @wire ids or called directly. If used as a @wire
+ * id, it must be the same object in the component under test and the test case
+ * itself. Due to this requirement, we save the mock to the global object to be
+ * shared.
+ */
+const resolvedPromiseTemplate = babelTemplate(`
+    let RESOURCE_NAME;
+    try {
+        RESOURCE_NAME = require(IMPORT_SOURCE).default;
+    } catch (e) {
+        global.MOCK_NAME = global.MOCK_NAME || function() { return Promise.resolve(); };
+        RESOURCE_NAME = global.MOCK_NAME;
+    }
+`);
+
+module.exports = function ({ types: t }) {
+    return {
+        visitor: {
+            ImportDeclaration(path) {
+                const { importSource, resourceNames } = getImportInfo(path, true);
+
+                if (importSource.startsWith(APEX_CONTINUATION_IMPORT_IDENTIFIER)) {
+                    // importing anything after '@salesforce/apexContinuation' means they're getting a single Apex method as the default import
+                    // e.g. `import myMethod from '@salesforce/apexContinuation/FooController.fooMethod';`
+                    path.replaceWithMultiple(resolvedPromiseTemplate({
+                        RESOURCE_NAME: t.identifier(resourceNames[0]),
+                        IMPORT_SOURCE: t.stringLiteral(importSource),
+                        MOCK_NAME: `__lwcJestMock_${resourceNames[0]}`,
+                    }));
+                }
+            }
+        }
+    };
+};