Support .node-version and .nvmrc by default; closes #683

__tests__/data/.node-version

@@ -0,0 +1 @@
+v16

__tests__/main.test.ts

@@ -155,14 +155,6 @@ describe('main tests', () => {
       expect(parseNodeVersionSpy).toHaveBeenCalledTimes(0);
     }, 10000);
 
-    it('not used if node-version-file not provided', async () => {
-      // Act
-      await main.run();
-
-      // Assert
-      expect(parseNodeVersionSpy).toHaveBeenCalledTimes(0);
-    });
-
     it('reads node-version-file if provided', async () => {
       // Arrange
       const versionSpec = 'v14';
@@ -215,6 +207,53 @@ describe('main tests', () => {
       );
     }, 10000);
 
+    it('reads .node-version if node-version and node-version-file were not provided', async () => {
+      // Arrange
+      const versionSpec = 'v16';
+      const versionFile = '.node-version';
+      const expectedVersionSpec = '16';
+      process.env['GITHUB_WORKSPACE'] = path.join(__dirname, 'data');
+
+      parseNodeVersionSpy.mockImplementation(() => expectedVersionSpec);
+      existsSpy.mockImplementationOnce(
+        input => input === path.join(__dirname, 'data', versionFile)
+      );
+
+      // Act
+      await main.run();
+
+      // Assert
+      expect(existsSpy).toHaveBeenCalledTimes(1);
+      expect(existsSpy).toHaveReturnedWith(true);
+      expect(parseNodeVersionSpy).toHaveBeenCalledWith(versionSpec);
+      expect(infoSpy).toHaveBeenCalledWith(
+        `Resolved ${versionFile} as ${expectedVersionSpec}`
+      );
+    }, 10000);
+
+    it('reads .nvmrc if node-version and node-version-file were not provided', async () => {
+      // Arrange
+      const versionSpec = 'v14';
+      const versionFile = '.nvmrc';
+      const expectedVersionSpec = '14';
+      process.env['GITHUB_WORKSPACE'] = path.join(__dirname, 'data');
+
+      parseNodeVersionSpy.mockImplementation(() => expectedVersionSpec);
+      existsSpy.mockImplementation(
+        input => input === path.join(__dirname, 'data', versionFile)
+      );
+
+      // Act
+      await main.run();
+
+      // Assert
+      expect(existsSpy).toHaveBeenCalledTimes(2);
+      expect(parseNodeVersionSpy).toHaveBeenCalledWith(versionSpec);
+      expect(infoSpy).toHaveBeenCalledWith(
+        `Resolved ${versionFile} as ${expectedVersionSpec}`
+      );
+    }, 10000);
+
     it('both node-version-file and node-version are provided', async () => {
       inputs['node-version'] = '12';
       const versionSpec = 'v14';

dist/setup/index.js

@@ -74003,11 +74003,22 @@ function resolveVersionInput() {
     }
     if (versionFileInput) {
         const versionFilePath = path.join(process.env.GITHUB_WORKSPACE, versionFileInput);
-        if (!fs_1.default.existsSync(versionFilePath)) {
-            throw new Error(`The specified node version file at: ${versionFilePath} does not exist`);
-        }
+        if (fs_1.default.existsSync(versionFilePath)) {
             version = util_1.parseNodeVersionFile(fs_1.default.readFileSync(versionFilePath, 'utf8'));
             core.info(`Resolved ${versionFileInput} as ${version}`);
+            return version;
+        }
+        else {
+            throw new Error(`The specified node version file at: ${versionFilePath} does not exist`);
+        }
+    }
+    for (const versionFile of ['.node-version', '.nvmrc']) {
+        const versionFilePath = path.join(process.env.GITHUB_WORKSPACE, versionFile);
+        if (fs_1.default.existsSync(versionFilePath)) {
+            version = util_1.parseNodeVersionFile(fs_1.default.readFileSync(versionFilePath, 'utf8'));
+            core.info(`Resolved ${versionFile} as ${version}`);
+            return version;
+        }
     }
     return version;
 }

src/main.ts

@@ -97,15 +97,32 @@ function resolveVersionInput(): string {
       versionFileInput
     );
 
-    if (!fs.existsSync(versionFilePath)) {
+    if (fs.existsSync(versionFilePath)) {
+      version = parseNodeVersionFile(fs.readFileSync(versionFilePath, 'utf8'));
+
+      core.info(`Resolved ${versionFileInput} as ${version}`);
+
+      return version;
+    } else {
       throw new Error(
         `The specified node version file at: ${versionFilePath} does not exist`
       );
     }
+  }
 
+  for (const versionFile of ['.node-version', '.nvmrc']) {
+    const versionFilePath = path.join(
+      process.env.GITHUB_WORKSPACE!,
+      versionFile
+    );
+
+    if (fs.existsSync(versionFilePath)) {
       version = parseNodeVersionFile(fs.readFileSync(versionFilePath, 'utf8'));
 
-    core.info(`Resolved ${versionFileInput} as ${version}`);
+      core.info(`Resolved ${versionFile} as ${version}`);
+
+      return version;
+    }
   }
 
   return version;