Refactored code and removed redundant logic

src/installer.ts

@@ -2,11 +2,18 @@ import os = require('os');
 import * as assert from 'assert';
 import * as core from '@actions/core';
 import * as io from '@actions/io';
+import * as hc from '@actions/http-client';
 import * as tc from '@actions/tool-cache';
 import * as path from 'path';
 import * as semver from 'semver';
 import fs = require('fs');
-import {INodeVersion, getVersionsFromDist} from './node-version';
+
+
+
+interface INodeVersion {
+  version: string;
+  files: string[];
+}
 
 interface INodeVersionInfo {
   downloadUrl: string;
@@ -376,6 +383,16 @@ async function queryDistForMatch(
   return version;
 }
 
+async function getVersionsFromDist(): Promise<INodeVersion[]> {
+  let dataUrl = 'https://nodejs.org/dist/index.json';
+  let httpClient = new hc.HttpClient('setup-node', [], {
+    allowRetries: true,
+    maxRetries: 3
+  });
+  let response = await httpClient.getJson<INodeVersion[]>(dataUrl);
+  return response.result || [];
+}
+
 // For non LTS versions of Node, the files we need (for Windows) are sometimes located
 // in a different folder than they normally are for other versions.
 // Normally the format is similar to: https://nodejs.org/dist/v5.10.1/node-v5.10.1-win-x64.7z
@@ -445,3 +462,32 @@ function translateArchToDistUrl(arch: string): string {
       return arch;
   }
 }
+
+export async function parseNodeVersionFile(contents: string): Promise<string> {
+  contents = contents.trim();
+
+  if (/^v\d/.test(contents)) {
+    contents = contents.substring(1);
+  }
+
+  const nodeVersions = await getVersionsFromDist();
+
+  let nodeVersion: string;
+
+  if (semver.valid(contents) || isPartialMatch(contents)) {
+    nodeVersion = contents;
+  } else {
+    throw new Error(`Couldn't resolve node version: '${contents}'`);
+  }
+
+  return stripVPrefix(nodeVersion);
+}
+
+function isPartialMatch(version: string): boolean {
+  return /^\d+(\.\d+(\.\d+)?)?$/.test(version);
+}
+
+function stripVPrefix(version: string): string {
+  return /^v\d/.test(version) ? version.substring(1) : version;
+}
+