fix(typeof-module): prevent unsupported declaration to be transformer when mocking typeof of a module that uses exports =

chore(module): add type to lambda

refactor(typeof-module): extract interface

Author: uittorio

src/transformer/descriptor/module/module.ts

@@ -42,35 +42,48 @@ function GetPropertiesFromSourceFileOrModuleDeclarationDescriptor(sourceFile: Ex
   return GetMockPropertiesFromDeclarations(GetPropertiesFromSourceFileOrModuleDeclaration(symbol, scope), [], scope);
 }
 
+interface ModuleExportsDeclarations {
+  declaration: ts.Declaration;
+  originalDeclaration: ts.NamedDeclaration;
+}
+
 export function GetPropertiesFromSourceFileOrModuleDeclaration(symbol: ts.Symbol, scope: Scope): ts.PropertySignature[] {
   const typeChecker: ts.TypeChecker = TypeChecker();
   const moduleExports: ts.Symbol[] = typeChecker.getExportsOfModule(symbol);
 
-  return moduleExports.map((prop: ts.Symbol): ts.PropertySignature => {
+  return moduleExports.map((prop: ts.Symbol): ModuleExportsDeclarations => {
     const originalSymbol: ts.Symbol = TypescriptHelper.GetAliasedSymbolSafe(prop);
-    const originalDeclaration: ts.NamedDeclaration = originalSymbol.declarations[0];
-    const declaration: ts.Declaration = prop.declarations[0];
-
-    if (ts.isExportAssignment(declaration)) {
-      return TypescriptCreator.createPropertySignature('default', ts.createTypeQueryNode(originalDeclaration.name as ts.Identifier));
-    }
+    const originalDeclaration: ts.NamedDeclaration = originalSymbol?.declarations?.[0];
+    const declaration: ts.Declaration = prop?.declarations?.[0];
+
+    return {
+      declaration,
+      originalDeclaration,
+    };
+  }).filter(
+    (d: ModuleExportsDeclarations) => !!d.originalDeclaration && d.declaration
+  ).map(
+    (d: ModuleExportsDeclarations): ts.PropertySignature => {
+      if (ts.isExportAssignment(d.declaration)) {
+        return TypescriptCreator.createPropertySignature('default', ts.createTypeQueryNode(d.originalDeclaration.name as ts.Identifier));
+      }
 
-    if (ts.isExportSpecifier(declaration) && ts.isSourceFile(originalDeclaration)) {
-      const exportSpecifierSymbol: ts.Symbol | undefined = typeChecker.getSymbolAtLocation(declaration.name);
+      if (ts.isExportSpecifier(d.declaration) && ts.isSourceFile(d.originalDeclaration)) {
+        const exportSpecifierSymbol: ts.Symbol | undefined = typeChecker.getSymbolAtLocation(d.declaration.name);
 
-      if (!exportSpecifierSymbol) {
-        throw new Error(
-          `The type checker failed to look up symbol for \`${declaration.name.getText()}'.`,
-        );
-      }
+        if (!exportSpecifierSymbol) {
+          throw new Error(
+            `The type checker failed to look up symbol for \`${d.declaration.name.getText()}'.`,
+          );
+        }
 
-      const exportSpecifierAliasSymbol: ts.Symbol = typeChecker.getAliasedSymbol(exportSpecifierSymbol);
-      const exportSpecifierProperties: ts.PropertySignature[] = GetPropertiesFromSourceFileOrModuleDeclaration(exportSpecifierAliasSymbol, scope);
-      const propertyType: ts.TypeNode = ts.createTypeLiteralNode(exportSpecifierProperties);
+        const exportSpecifierAliasSymbol: ts.Symbol = typeChecker.getAliasedSymbol(exportSpecifierSymbol);
+        const exportSpecifierProperties: ts.PropertySignature[] = GetPropertiesFromSourceFileOrModuleDeclaration(exportSpecifierAliasSymbol, scope);
+        const propertyType: ts.TypeNode = ts.createTypeLiteralNode(exportSpecifierProperties);
 
-      return TypescriptCreator.createPropertySignature(declaration.name, propertyType);
-    }
+        return TypescriptCreator.createPropertySignature(d.declaration.name, propertyType);
+      }
 
-    return TypescriptCreator.createPropertySignature(originalDeclaration.name as ts.Identifier, ts.createTypeQueryNode(originalDeclaration.name as ts.Identifier));
-  });
+      return TypescriptCreator.createPropertySignature(d.originalDeclaration.name as ts.Identifier, ts.createTypeQueryNode(d.originalDeclaration.name as ts.Identifier));
+    });
 }

test/transformer/descriptor/typeQuery/typeQuery.test.ts

@@ -61,6 +61,7 @@ describe('typeQuery', () => {
 
     it('should return correct properties with multiple declarations', () => {
       function MultipleDeclaration(): MultipleDeclaration {
+        // eslint-disable-next-line @typescript-eslint/ban-ts-comment
         // @ts-ignore
         return { a: 's'};
       }
@@ -71,6 +72,7 @@ describe('typeQuery', () => {
 
       const functionMock: typeof MultipleDeclaration = createMock<typeof MultipleDeclaration>();
 
+      // eslint-disable-next-line @typescript-eslint/ban-ts-comment
       // @ts-ignore
       expect(functionMock()).toEqual({
         b: '',

test/transformer/descriptor/typeQuery/typeQueryExportClasses.test.ts

@@ -0,0 +1,13 @@
+import { createMock } from 'ts-auto-mock';
+import exportEqual = require('../utils/export/exportEqual');
+
+describe('TypeQuery export equal classes', () => {
+  it('should exclude the class and not fail', () => {
+    // When transforming typeof a module there are some scenario that are not playing nicely with ts-auto-mock implementation
+    // Ts auto mock uses typeChecker getExportsOfModule functionality to find symbols
+    // When the module uses export = ClassName ts auto mock will find the prototype but it will not be able to find the original declaration.
+    const mock: typeof exportEqual = createMock<typeof exportEqual>();
+
+    expect(mock).toBeDefined();
+  });
+});

test/transformer/descriptor/typeQuery/typeQueryUndefined.test.ts

@@ -6,6 +6,7 @@ describe('typeQuery undefined ', () => {
     // make sure if a set of type declarations are faulty (from DefinitelyTyped
     // for example) they will "fail" silently.
 
+    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
     // @ts-ignore
     const type: typeof undefined = createMock<typeof undefined>();
 

test/transformer/descriptor/utils/export/exportEqual.ts

@@ -0,0 +1,11 @@
+declare namespace Test {
+  interface HelloWorld {
+    prop: string;
+  }
+}
+
+class Test {
+  public a: string;
+}
+
+export = Test;