fix(genericNotProvided): make sure required generic will default to n…

…ull when are not provided (#180)
Typescript-TDD · Jan 16, 2020 · ad76471 · ad76471
1 parent 5b02465
commit ad76471
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Showing 3 changed files with 30 additions and 9 deletions.
diff --git a/src/transformer/descriptor/module/module.ts b/src/transformer/descriptor/module/module.ts
@@ -2,7 +2,6 @@ import * as ts from 'typescript';
 import { TypescriptCreator } from '../../helper/creator';
 import { Scope } from '../../scope/scope';
 import { TypeChecker } from '../../typeChecker/typeChecker';
-import { GetDescriptor } from '../descriptor';
 import { TypescriptHelper } from '../helper/helper';
 import { GetMockPropertiesFromDeclarations } from '../mock/mockProperties';
 import { PropertyLike } from '../mock/propertyLike';

diff --git a/src/transformer/genericDeclaration/genericDeclaration.ts b/src/transformer/genericDeclaration/genericDeclaration.ts
@@ -15,8 +15,12 @@ export function GenericDeclaration(scope: Scope): IGenericDeclaration {
         return !!node.typeArguments && !!node.typeArguments[index];
     }
 
-    function getGenericTypeNode(node: ts.TypeReferenceNode | ts.ExpressionWithTypeArguments, nodeDeclaration: ts.TypeParameterDeclaration, index: number): ts.TypeNode {
-        return isGenericProvided(node, index) ? node.typeArguments[index] : nodeDeclaration.default;
+    function getGenericNode(node: ts.TypeReferenceNode | ts.ExpressionWithTypeArguments, nodeDeclaration: ts.TypeParameterDeclaration, index: number): ts.Node {
+        if (isGenericProvided(node, index)) {
+          return node.typeArguments[index];
+        }
+
+        return nodeDeclaration.default || ts.createNull();
     }
 
     function addGenericParameterToExisting(
@@ -55,12 +59,12 @@ export function GenericDeclaration(scope: Scope): IGenericDeclaration {
             }
 
             typeParameterDeclarations.forEach((declaration: ts.TypeParameterDeclaration, index: number) => {
-                const genericTypeNode: ts.TypeNode = getGenericTypeNode(node, declaration, index);
+                const genericNode: ts.Node = getGenericNode(node, declaration, index);
 
                 const genericParameter: GenericParameter = createGenericParameter(
                     declarationKey,
                     typeParameterDeclarations[index],
-                    GetDescriptor(genericTypeNode, scope));
+                    GetDescriptor(genericNode, scope));
 
                 generics.push(genericParameter);
             });
@@ -78,10 +82,10 @@ export function GenericDeclaration(scope: Scope): IGenericDeclaration {
             }
 
             extensionDeclarationTypeParameters.reduce((acc: GenericParameter[], declaration: ts.TypeParameterDeclaration, index: number) => {
-                const genericTypeNode: ts.TypeNode = getGenericTypeNode(extension, declaration, index);
+                const genericNode: ts.Node = getGenericNode(extension, declaration, index);
 
-                if (ts.isTypeReferenceNode(genericTypeNode)) {
-                    const typeParameterDeclaration: ts.Declaration = TypescriptHelper.GetDeclarationFromNode(genericTypeNode.typeName);
+                if (ts.isTypeReferenceNode(genericNode)) {
+                    const typeParameterDeclaration: ts.Declaration = TypescriptHelper.GetDeclarationFromNode(genericNode.typeName);
                     if (ts.isTypeParameterDeclaration(typeParameterDeclaration)) {
                         addGenericParameterToExisting(
                             extensionDeclarationTypeParameters[index],
@@ -97,7 +101,7 @@ export function GenericDeclaration(scope: Scope): IGenericDeclaration {
                 const genericParameter: GenericParameter = createGenericParameter(
                     extensionDeclarationKey,
                     extensionDeclarationTypeParameters[index],
-                    GetDescriptor(genericTypeNode, scope),
+                    GetDescriptor(genericNode, scope),
                 );
 
                 acc.push(genericParameter);

diff --git a/test/transformer/descriptor/generic/null.test.ts b/test/transformer/descriptor/generic/null.test.ts
@@ -0,0 +1,18 @@
+import { createMock } from 'ts-auto-mock';
+
+describe('generic null', () => {
+    it('should assign null value when not provided even if it was supposed to', () => {
+        interface A<P> {
+            prop: P;
+            data: {
+              a: string;
+            };
+        }
+
+        // @ts-ignore
+        const mock: A = createMock<A>();
+
+        expect(mock.prop).toBeNull();
+        expect(mock.data.a).toBe('');
+    });
+});