Do not let lodash parse module names as path elements

Author: Frank Schmid

lib/packExternalModules.js

@@ -41,10 +41,10 @@ function getProdModules(externalModules, packagePath, dependencyGraph) {
       } catch (e) {
         this.serverless.cli.log(`WARNING: Could not check for peer dependencies of ${module.external}`);
       }
-    } else if (!_.has(packageJson, `devDependencies.${module.external}`)) {
+    } else if (!packageJson.devDependencies || !packageJson.devDependencies[module.external]) {
       // Add transient dependencies if they appear not in the service's dev dependencies
-      const originInfo = _.get(dependencyGraph, `dependencies.${module.origin}`, {});
-      moduleVersion = _.get(originInfo, `dependencies.${module.external}.version`);
+      const originInfo = _.get(dependencyGraph, 'dependencies', {})[module.origin] || {};
+      moduleVersion = _.get(_.get(originInfo, 'dependencies', {})[module.external], 'version');
       if (!moduleVersion) {
         this.serverless.cli.log(`WARNING: Could not determine version of module ${module.external}`);
       }
@@ -208,7 +208,8 @@ module.exports = {
           splitModule[0] = '@' + splitModule[0];
         }
         const moduleVersion = _.join(_.tail(splitModule), '@');
-        _.set(compositePackage, `dependencies.${_.first(splitModule)}`, moduleVersion);
+        compositePackage.dependencies = compositePackage.dependencies || {};
+        compositePackage.dependencies[_.first(splitModule)] = moduleVersion;
       });
       this.serverless.utils.writeFileSync(compositePackageJson, JSON.stringify(compositePackage, null, 2));