Implemented support for repository defined node version files such as '.nvmrc'

README.md

@@ -55,6 +55,21 @@ steps:
 - run: npm test
 ```
 
+Node version file:
+
+The `node-version-file` input allows you to use a file within your repository which contains the version of node your project uses for example `.nvmrc`. If both the `node-version` and the `node-version-file` inputs are provided the `node-version` input is used.
+> The node version file is read from the project root
+
+```yaml
+steps:
+- uses: actions/checkout@v2
+- uses: actions/setup-node@v2
+  with:
+    node-version-file: '.nvmrc'
+- run: npm install
+- run: npm test
+```
+
 Matrix Testing:
 ```yaml
 jobs:

__tests__/installer.test.ts

@@ -36,6 +36,7 @@ describe('setup-node', () => {
   let dbgSpy: jest.SpyInstance;
   let whichSpy: jest.SpyInstance;
   let existsSpy: jest.SpyInstance;
+  let readFileSyncSpy: jest.SpyInstance;
   let mkdirpSpy: jest.SpyInstance;
   let execSpy: jest.SpyInstance;
   let authSpy: jest.SpyInstance;
@@ -67,6 +68,7 @@ describe('setup-node', () => {
     // io
     whichSpy = jest.spyOn(io, 'which');
     existsSpy = jest.spyOn(fs, 'existsSync');
+    readFileSyncSpy = jest.spyOn(fs, 'readFileSync');
     mkdirpSpy = jest.spyOn(io, 'mkdirP');
 
     // disable authentication portion for installer tests
@@ -490,4 +492,48 @@ describe('setup-node', () => {
       expect(cnSpy).toHaveBeenCalledWith(`::add-path::${expPath}${osm.EOL}`);
     });
   });
+
+  describe('node-version-file flag', () => {
+    it('Not used if node-version is provided', async () => {
+      // Arrange
+      inputs['node-version'] = '12';
+
+      // Act
+      await main.run();
+
+      // Assert
+      expect(readFileSyncSpy).toHaveBeenCalledTimes(0);
+    });
+
+    it('Not used if node-version-file not provided', async () => {
+      // Act
+      await main.run();
+
+      // Assert
+      expect(readFileSyncSpy).toHaveBeenCalledTimes(0);
+    });
+
+    it('Reads node-version-file if provided', async () => {
+      // Arrange
+      const versionSpec = 'v12';
+      const versionFile = '.nvmrc';
+
+      inputs['node-version-file'] = versionFile;
+
+      readFileSyncSpy.mockImplementation(() => versionSpec);
+
+      // Act
+      await main.run();
+
+      // Assert
+      expect(readFileSyncSpy).toHaveBeenCalledTimes(1);
+      expect(readFileSyncSpy).toHaveBeenCalledWith(
+        path.join(__dirname, '..', versionFile),
+        'utf8'
+      );
+      expect(logSpy).toHaveBeenCalledWith(
+        `Resolved ${versionFile} as ${versionSpec}`
+      );
+    });
+  });
 });

action.yml

@@ -7,6 +7,8 @@ inputs:
     default: 'false'
   node-version:
     description: 'Version Spec of the version to use.  Examples: 12.x, 10.15.1, >=10.15.0'
+  node-version-file:
+    description: 'File containing the version Spec of the version to use.  Examples: .nvmrc'
   check-latest:
     description: 'Set this option if you want the action to check for the latest available version that satisfies the version spec'
     default: false

dist/index.js

@@ -4692,6 +4692,7 @@ Object.defineProperty(exports, "__esModule", { value: true });
 const core = __importStar(__webpack_require__(470));
 const installer = __importStar(__webpack_require__(749));
 const auth = __importStar(__webpack_require__(202));
+const fs = __webpack_require__(747);
 const path = __importStar(__webpack_require__(622));
 const url_1 = __webpack_require__(835);
 function run() {
@@ -4705,6 +4706,14 @@ function run() {
             if (!version) {
                 version = core.getInput('version');
             }
+            if (!version) {
+                const versionFile = core.getInput('node-version-file');
+                if (!!versionFile) {
+                    const versionFilePath = path.join(__dirname, '..', versionFile);
+                    version = fs.readFileSync(versionFilePath, 'utf8');
+                    core.info(`Resolved ${versionFile} as ${version}`);
+                }
+            }
             if (version) {
                 let token = core.getInput('token');
                 let auth = !token || isGhes() ? undefined : `token ${token}`;

src/main.ts

@@ -1,6 +1,7 @@
 import * as core from '@actions/core';
 import * as installer from './installer';
 import * as auth from './authutil';
+import fs = require('fs');
 import * as path from 'path';
 import {URL} from 'url';
 
@@ -15,6 +16,16 @@ export async function run() {
       version = core.getInput('version');
     }
 
+    if (!version) {
+      const versionFile = core.getInput('node-version-file');
+
+      if (!!versionFile) {
+        const versionFilePath = path.join(__dirname, '..', versionFile);
+        version = fs.readFileSync(versionFilePath, 'utf8');
+        core.info(`Resolved ${versionFile} as ${version}`);
+      }
+    }
+
     if (version) {
       let token = core.getInput('token');
       let auth = !token || isGhes() ? undefined : `token ${token}`;