Applied suggestions on PR ehmicky#1 and made '_' the default for '.' when no version file

Author: AdrieanKhisbe

README.md

@@ -7,6 +7,9 @@
 
 Normalize and validate Node.js versions
 
+Can guess the current project's version using its `.nvmrc` if you use supported
+[aliases](#supported-aliases)
+
 # Example
 
 <!-- Remove 'eslint-skip' once estree supports top-level await -->
@@ -22,7 +25,7 @@ await normalizeNodeVersion('8.5.2') // Error: Invalid Node version
 await normalizeNodeVersion('<7') // '6.17.1'
 await normalizeNodeVersion('*') // Latest Node version, e.g. '12.8.0'
 await normalizeNodeVersion('_') // Node version used by current process
-await normalizeNodeVersion('.') // Node version of project specified in either .node-version, .nvmrc or .naverc
+await normalizeNodeVersion('.') // Node version from a '.nvmrc', '.node-version' or '.naverc' file in the current directory or any parent directory
 await normalizeNodeVersion('not_a_version') // Error: Invalid Node version
 
 // All available options
@@ -74,6 +77,16 @@ _Default_: `process.cwd()`
 Folder to consider to start look for a node version file when using the `.`
 alias (`.node-version`, `.nvmrc` or `.naverc`)
 
+### Supported aliases
+
+`normalizeNodeVersion` support some node version aliases you can use as
+`versionRange`:
+
+- `_` : Node version used by current process
+- `.` : Node version from a `.nvmrc`, `.node-version` or `.naverc` file in the
+  current directory or any parent directory If no version file is found, it will
+  resolve to current process version.
+
 # See also
 
 - [`nve`](https://github.com/ehmicky/nve): Run a specific Node.js version (CLI)

src/aliases.js

@@ -1,5 +1,5 @@
 import { promises as fs } from 'fs'
-import { version } from 'process'
+import { version as processVersion } from 'process'
 
 import findUp from 'find-up'
 
@@ -8,24 +8,25 @@ export const NODE_VERSION_FILES = ['.node-version', '.nvmrc', '.naverc']
 
 export const CURRENT_NODE_ALIAS = '_'
 
+export const resolveNodeVersionAlias = async ({ cwd } = {}) => {
+  const nodeVersionFile = await findUp(NODE_VERSION_FILES, { cwd })
+  if (nodeVersionFile === undefined) return
+
+  const nodeVersionFileContent = await fs.readFile(nodeVersionFile, 'utf-8')
+  return nodeVersionFileContent.trim()
+}
+
 export const resolveVersionRangeAlias = async function (
   versionRange,
   { cwd } = {},
 ) {
-  if (versionRange === CURRENT_NODE_ALIAS) return version
-
-  if (versionRange !== NODE_VERSION_ALIAS) return versionRange
+  if (versionRange === CURRENT_NODE_ALIAS) return processVersion
 
-  const nodeVersionFile = await findUp(NODE_VERSION_FILES, { cwd })
+  if (versionRange === NODE_VERSION_ALIAS) {
+    const resolvedVersion = await resolveNodeVersionAlias({ cwd })
 
-  if (nodeVersionFile === undefined) {
-    throw new Error(
-      `node config file not found [was looking for ${NODE_VERSION_FILES.join(
-        ', ',
-      )}]`,
-    )
+    return resolvedVersion || processVersion
   }
 
-  const nodeVersionFileContent = await fs.readFile(nodeVersionFile, 'utf-8')
-  return nodeVersionFileContent.trim()
+  return versionRange
 }

test/aliases.js

@@ -1,4 +1,3 @@
-import { join } from 'path'
 import { version } from 'process'
 
 import test from 'ava'
@@ -7,7 +6,7 @@ import { resolveVersionRangeAlias } from '../src/aliases.js'
 
 const resolveInFolder = (versionRange, folder) =>
   resolveVersionRangeAlias(versionRange, {
-    cwd: join(__dirname, 'fixtures', folder),
+    cwd: `${__dirname}/fixtures/${folder}`,
   })
 
 test('Resolve - with node-version pseudo version', async (t) => {
@@ -30,10 +29,11 @@ test('Resolve - in mixed project pseudo version, .node-version having precedence
   t.is(versionRange, 'v12.12', 'not resolved to .node-version')
 })
 
-test('Throw error if resolving - and none of the node version files are found', async (t) => {
-  await t.throwsAsync(
-    resolveVersionRangeAlias('.', { cwd: join(__dirname, '..', 'src') }),
-  )
+test('Resolve -  default to process.version if no version file found', async (t) => {
+  const versionRange = await resolveVersionRangeAlias('.', {
+    cwd: `${__dirname}/../src`,
+  })
+  t.is(versionRange, version, 'not resolved to .node-version')
 })
 
 test('Resolve current node pseudo version', async (t) => {