fix: ensure falsy enum values are still mapped (#7900)

* fix: ensure falsy enum values are still mapped

* Create spotty-waves-whisper.md

Co-authored-by: Saihajpreet Singh <saihajpreet.singh@gmail.com>

Author: georgehb

.changeset/spotty-waves-whisper.md

@@ -0,0 +1,6 @@
+---
+"@graphql-codegen/typescript": patch
+"@graphql-codegen/visitor-plugin-common": patch
+---
+
+Ensure falsy enum values are still mapped

packages/plugins/other/visitor-plugin-common/src/enum-values.ts

@@ -24,7 +24,7 @@ export function parseEnumValues({
       for (const enumTypeName of allEnums) {
         const enumType = schema.getType(enumTypeName) as GraphQLEnumType;
         for (const { name, value } of enumType.getValues()) {
-          if (value && value !== name) {
+          if (value !== name) {
             mapOrStr[enumTypeName] = mapOrStr[enumTypeName] || {};
             if (typeof mapOrStr[enumTypeName] !== 'string' && !mapOrStr[enumTypeName][name]) {
               mapOrStr[enumTypeName][name] = typeof value === 'string' ? escapeString(value) : value;

packages/plugins/typescript/typescript/tests/typescript.spec.ts

@@ -637,6 +637,38 @@ describe('TypeScript', () => {
       expect(output).toContain(`SomethingElse = '99'`);
     });
 
+    it('#7898 - falsy enum value set on schema with enumsAsTypes set', async () => {
+      const testSchema = new GraphQLSchema({
+        types: [
+          new GraphQLObjectType({
+            name: 'Query',
+            fields: {
+              test: {
+                type: new GraphQLEnumType({
+                  name: 'MyEnum',
+                  values: {
+                    EnumValueName: {
+                      value: 0,
+                    },
+                  },
+                }),
+              },
+            },
+          }),
+        ],
+      });
+
+      const result = (await plugin(
+        testSchema,
+        [],
+        { enumsAsTypes: true },
+        { outputFile: '' }
+      )) as Types.ComplexPluginOutput;
+      const output = mergeOutputs([result]);
+      expect(output).not.toContain('EnumValueName');
+      expect(output).toContain('0');
+    });
+
     it('#6532 - numeric enum values with namingConvention', async () => {
       const testSchema = buildSchema(/* GraphQL */ `
         type Query {