Move ts-node as optional dependency

That dependency must be added by the user only if they use TypeScript.
An error will be throw if the dependency is not added and the serverless-webpack configuration is written in TypeScript.

Author: j0k3r

index.js

@@ -32,7 +32,11 @@ class ServerlessWebpack {
       (_.has(this.serverless, 'service.custom.webpack.webpackConfig') &&
         _.endsWith(this.serverless.service.custom.webpack.webpackConfig, '.ts'))
     ) {
-      require('ts-node/register');
+      try {
+        require('ts-node/register');
+      } catch (e) {
+        throw new Error('If you want to use TypeScript with serverless-webpack, please add "ts-node" as dependency.');
+      }
     }
 
     _.assign(

index.test.js

@@ -20,6 +20,7 @@ describe('ServerlessWebpack', () => {
   let sandbox;
   let serverless;
   let ServerlessWebpack;
+  let moduleStub;
 
   before(function() {
     // Mockery might take some time to clear the cache. So add 3 seconds to the default timeout.
@@ -32,7 +33,7 @@ describe('ServerlessWebpack', () => {
     mockery.registerMock('webpack', {});
 
     ServerlessWebpack = require('./index');
-    sandbox.spy(Module, '_load');
+    moduleStub = sandbox.stub(Module, '_load');
   });
 
   beforeEach(() => {
@@ -83,6 +84,25 @@ describe('ServerlessWebpack', () => {
       expect(Module._load).to.have.been.calledOnce;
       expect(Module._load).to.have.been.calledWith('ts-node/register');
     });
+
+    it('should throw an error if config use TS but ts-node was not added as dependency', () => {
+      moduleStub.throws();
+
+      _.set(serverless, 'service.custom.webpack.webpackConfig', 'webpack.config.ts');
+
+      const badDeps = function() {
+        new ServerlessWebpack(serverless, {});
+      };
+
+      expect(badDeps).to.throw(
+        'If you want to use TypeScript with serverless-webpack, please add "ts-node" as dependency.'
+      );
+
+      expect(Module._load).to.have.been.calledOnce;
+      expect(Module._load).to.have.been.calledWith('ts-node/register');
+
+      moduleStub.reset();
+    });
   });
 
   describe('with a JS webpack configuration', () => {

lib/packExternalModules.js

@@ -442,4 +442,3 @@ module.exports = {
     });
   }
 };
-

package-lock.json

@@ -55,8 +55,7 @@
     "glob": "^7.1.4",
     "is-builtin-module": "^3.0.0",
     "lodash": "^4.17.19",
-    "semver": "^6.2.0",
-    "ts-node": "^8.3.0"
+    "semver": "^6.2.0"
   },
   "devDependencies": {
     "babel-eslint": "^10.0.2",
@@ -80,5 +79,8 @@
   },
   "peerDependencies": {
     "webpack": ">= 3.0.0 < 6"
+  },
+  "optionalDependencies": {
+    "ts-node": ">= 8.3.0"
   }
 }

package.json

@@ -216,14 +216,12 @@ describe('validate', () => {
     it('should turn NodeStuffPlugin and NodeSourcePlugin plugins off by default', () => {
       const testEntry = 'testentry';
       const testConfig = {
-        entry: testEntry,
+        entry: testEntry
       };
       const testServicePath = 'testpath';
       module.serverless.config.servicePath = testServicePath;
       _.set(module.serverless.service, 'custom.webpack.config', testConfig);
-      return module
-        .validate()
-        .then(() => expect(module.webpackConfig.node).to.eql(false));
+      return module.validate().then(() => expect(module.webpackConfig.node).to.eql(false));
     });
   });
 
@@ -913,4 +911,3 @@ describe('validate', () => {
     });
   });
 });
-