Do not run webpack on a single non-node function

index.js

@@ -14,6 +14,7 @@ const prepareOfflineInvoke = require('./lib/prepareOfflineInvoke');
 const prepareStepOfflineInvoke = require('./lib/prepareStepOfflineInvoke');
 const packExternalModules = require('./lib/packExternalModules');
 const packageModules = require('./lib/packageModules');
+const { isNodeRuntime } = require('./lib/utils');
 const lib = require('./lib');
 
 class ServerlessWebpack {
@@ -104,11 +105,16 @@ class ServerlessWebpack {
 
       'after:package:createDeploymentArtifacts': () => BbPromise.bind(this).then(this.cleanup),
 
-      'before:deploy:function:packageFunction': () =>
-        BbPromise.bind(this)
-          .then(() => this.serverless.pluginManager.spawn('webpack:validate'))
-          .then(() => this.serverless.pluginManager.spawn('webpack:compile'))
-          .then(() => this.serverless.pluginManager.spawn('webpack:package')),
+      'before:deploy:function:packageFunction': () => {
+        const runtime = this.serverless.service.getFunction(this.options.function).runtime;
+
+        if (isNodeRuntime(runtime)) {
+          return BbPromise.bind(this)
+            .then(() => this.serverless.pluginManager.spawn('webpack:validate'))
+            .then(() => this.serverless.pluginManager.spawn('webpack:compile'))
+            .then(() => this.serverless.pluginManager.spawn('webpack:package'));
+        }
+      },
 
       'before:invoke:local:invoke': () =>
         BbPromise.bind(this)

index.test.js

@@ -44,6 +44,7 @@ describe('ServerlessWebpack', () => {
     };
 
     sandbox.stub(serverless.pluginManager, 'spawn').returns(BbPromise.resolve());
+    sandbox.stub(serverless.service, 'getFunction').returns({ runtime: 'nodejs12.x' });
   });
 
   afterEach(() => {
@@ -222,6 +223,8 @@ describe('ServerlessWebpack', () => {
           name: 'before:deploy:function:packageFunction',
           test: () => {
             it('should spawn validate, compile and package', () => {
+              slsw.options.function = functionName;
+
               return expect(slsw.hooks['before:deploy:function:packageFunction']()).to.be.fulfilled.then(() => {
                 expect(slsw.serverless.pluginManager.spawn).to.have.been.calledThrice;
                 expect(slsw.serverless.pluginManager.spawn.firstCall).to.have.been.calledWithExactly(

lib/utils.js

@@ -108,12 +108,16 @@ function splitLines(str) {
   return _.split(str, /\r?\n/);
 }
 
+function isNodeRuntime(runtime) {
+  return runtime.match(/node/);
+}
+
 function getAllNodeFunctions() {
   const functions = this.serverless.service.getAllFunctions();
   return _.filter(functions, funcName => {
     const func = this.serverless.service.getFunction(funcName);
-    const runtime = func.runtime || this.serverless.service.provider.runtime || 'nodejs';
-    return runtime.match(/node/);
+
+    return isNodeRuntime(func.runtime || this.serverless.service.provider.runtime || 'nodejs');
   });
 }
 
@@ -125,5 +129,6 @@ module.exports = {
   spawnProcess,
   safeJsonParse,
   splitLines,
-  getAllNodeFunctions
+  getAllNodeFunctions,
+  isNodeRuntime
 };

lib/validate.js

@@ -7,7 +7,7 @@ const glob = require('glob');
 const lib = require('./index');
 const _ = require('lodash');
 const Configuration = require('./Configuration');
-const { getAllNodeFunctions } = require('./utils');
+const { getAllNodeFunctions, isNodeRuntime } = require('./utils');
 
 /**
  * For automatic entry detection we sort the found files to solve ambiguities.
@@ -120,7 +120,7 @@ module.exports = {
         const loadedFunc = this.serverless.service.getFunction(func);
         const runtime = loadedFunc.runtime || this.serverless.service.provider.runtime || 'nodejs';
 
-        if (runtime.match(/node/)) {
+        if (isNodeRuntime(runtime)) {
           // runtimes can be 'nodejsX.Y' (AWS, Azure) or 'google-nodejs' (Google Cloud)
           const entry = getEntryForFunction.call(this, functions[index], loadedFunc);
           _.merge(entries, entry);
@@ -227,6 +227,7 @@ module.exports = {
           const func = this.serverless.service.getFunction(funcName);
           const handler = getHandlerFileAndFunctionName(func);
           const handlerFile = path.relative('.', getHandlerFile(handler));
+
           return {
             handlerFile,
             funcName,
@@ -271,8 +272,8 @@ module.exports = {
     // Webpack config can be a Promise, If it's a Promise wait for resolved config object.
     if (this.webpackConfig && _.isFunction(this.webpackConfig.then)) {
       return BbPromise.resolve(this.webpackConfig.then(config => processConfig(config)));
-    } else {
-      return processConfig(this.webpackConfig);
     }
+
+    return processConfig(this.webpackConfig);
   }
 };