Do not call npm install if everything is installed

lib/npm-installation-manager.ts

@@ -84,7 +84,7 @@ export class NpmInstallationManager implements INpmInstallationManager {
 				.sortBy(verData => verData.patch)
 				.value();
 
-			let result = _.last(compatibleVersions);
+			let result = _.last(compatibleVersions) || this.getVersionData(latestVersion);
 
 			let latestCompatibleVersion = `${result.major}.${result.minor}.${result.patch}`;
 			return latestCompatibleVersion;

lib/services/plugins-service.ts

@@ -161,11 +161,15 @@ export class PluginsService implements IPluginsService {
 
 	public ensureAllDependenciesAreInstalled(): IFuture<void> {
 		return (() => {
-			let command = "npm install ";
-			if(this.$options.ignoreScripts) {
-				command += "--ignore-scripts";
+			let installedDependencies = this.$fs.exists(this.nodeModulesPath).wait() ? this.$fs.readDirectory(this.nodeModulesPath).wait() : [];
+			let packageJsonContent = this.$fs.readJson(this.getPackageJsonFilePath()).wait();
+			if(this.$options.force || (packageJsonContent.dependencies && _.difference(_.keys(packageJsonContent.dependencies), installedDependencies).length)) {
+				let command = "npm install ";
+				if(this.$options.ignoreScripts) {
+					command += "--ignore-scripts";
+				}
+				this.$childProcess.exec(command, { cwd: this.$projectData.projectDir }).wait();
 			}
-			this.$childProcess.exec(command, { cwd: this.$projectData.projectDir }).wait();
 		}).future<void>()();
 	}
 

test/npm-installation-manager.ts

@@ -72,6 +72,7 @@ describe("Npm installation manager tests", () => {
 		let expectedLatestCompatibleVersion = "1.4.0";
 		assert.equal(actualLatestCompatibleVersion, expectedLatestCompatibleVersion);
 	});
+
 	it("returns correct latest compatible version", () => {
 		let testInjector = createTestInjector();
 
@@ -92,4 +93,23 @@ describe("Npm installation manager tests", () => {
 		let expectedLatestCompatibleVersion = "1.3.3";
 		assert.equal(actualLatestCompatibleVersion, expectedLatestCompatibleVersion);
 	});
+
+	it("returns correct latest compatible version", () => {
+		let testInjector = createTestInjector();
+
+		let versions = ["1.2.0", "1.3.0", "1.3.1", "1.3.2", "1.3.3", "1.4.0"];
+		let latestVersion = _.last(versions);
+		mockNpm(testInjector, versions, latestVersion);
+
+		// Mock staticConfig.version
+		let staticConfig = testInjector.resolve("staticConfig");
+		staticConfig.version = "1.5.0";
+
+		// Mock npmInstallationManager.getLatestVersion
+		let npmInstallationManager = testInjector.resolve("npmInstallationManager");
+		npmInstallationManager.getLatestVersion = (packageName: string) => Future.fromResult(latestVersion);
+
+		let actualLatestCompatibleVersion = npmInstallationManager.getLatestCompatibleVersion("").wait();
+		assert.equal(actualLatestCompatibleVersion, latestVersion);
+	});
 });