feat: add support for different type of dependencies

.gitignore

@@ -3,3 +3,5 @@ npm-debug.log
 .npmrc
 # output
 dist
+.DS_Store
+*.log

lib/index.ts

@@ -18,6 +18,16 @@ interface PkgTree {
   hasDevDependencies?: boolean;
 }
 
+interface TargetFile {
+  name?: string;
+  dependencies?: {
+    [dep: string]: object;
+  };
+  devDependencies?: {
+    [dep: string]: object;
+  };
+}
+
 export {
   buildDepTree,
   buildDepTreeFromFiles,
@@ -30,12 +40,9 @@ async function buildDepTree(targetFileRaw: string, lockFileRaw: string, includeD
   const lockFile = JSON.parse(lockFileRaw);
   const targetFile = JSON.parse(targetFileRaw);
 
-  if (!targetFile.dependencies) {
+  if (!targetFile.dependencies && !includeDev) {
     throw new Error("No 'dependencies' property in package.json");
   }
-  if (!lockFile.dependencies) {
-    throw new Error("No 'dependencies' property in package-lock.json");
-  }
 
   const depTree: PkgTree = {
     dependencies: {},
@@ -44,23 +51,38 @@ async function buildDepTree(targetFileRaw: string, lockFileRaw: string, includeD
     version: targetFile.version,
   };
 
-  const topLevelDeps = Object.keys(targetFile.dependencies);
+  // asked to process empty deps
+  if (_.isEmpty(targetFile.dependencies) && !includeDev) {
+    return depTree;
+  }
+
+  if (!lockFile.dependencies && !includeDev) {
+    throw new Error("No 'dependencies' property in package-lock.json");
+  }
+  const topLevelDeps = getTopLevelDeps(targetFile, includeDev);
 
   await Promise.all(topLevelDeps.map(async (dep) => {
     depTree.dependencies[dep] = await buildSubTreeRecursive(dep, [], lockFile);
   }));
 
+  return depTree;
+}
+
+function getTopLevelDeps(targetFile: TargetFile, includeDev: boolean): string[] {
+  let topLevelDeps = targetFile.dependencies;
+
   if (includeDev && targetFile.devDependencies) {
-    const topLevelDevDeps = Object.keys(targetFile.devDependencies);
-    await Promise.all(topLevelDevDeps.map(async (dep) => {
-      depTree.dependencies[dep] = await buildSubTreeRecursive(dep, [], lockFile);
-    }));
+    topLevelDeps = {
+      ...topLevelDeps,
+      ...targetFile.devDependencies,
+    };
   }
 
-  return depTree;
+  return _.uniq(Object.keys(topLevelDeps));
 }
 
-async function buildSubTreeRecursive(dep: string, depKeys: string[], lockFile: object): Promise<PkgTree> {
+async function buildSubTreeRecursive(
+  dep: string, depKeys: string[], lockFile: object): Promise<PkgTree> {
 
   const depSubTree: PkgTree = {
     depType: undefined,
@@ -82,9 +104,12 @@ async function buildSubTreeRecursive(dep: string, depKeys: string[], lockFile: o
     depSubTree.depType = deps[dep].dev ? DepType.dev : DepType.prod;
     // repeat the process for dependencies of looked-up dep
     const newDeps = deps[dep].requires ? Object.keys(deps[dep].requires) : [];
+
     await Promise.all(newDeps.map(async (subDep) => {
-      depSubTree.dependencies[subDep] = await buildSubTreeRecursive(subDep, [...depKeys, dep], lockFile);
-    }));
+      depSubTree.dependencies[subDep] = await buildSubTreeRecursive(subDep,
+          [...depKeys, dep], lockFile);
+      }),
+    );
     return depSubTree;
   } else {
     // tree was walked to the root and dependency was not found
@@ -109,7 +134,7 @@ function getDepPath(depKeys: string[]) {
 async function buildDepTreeFromFiles(
   root: string, targetFilePath: string, lockFilePath: string, includeDev = false): Promise<PkgTree> {
   if (!root || !lockFilePath || !lockFilePath) {
-    throw new Error('Missing required parameters for parseLockFile()');
+    throw new Error('Missing required parameters for buildDepTreeFromFiles()');
   }
 
   const targetFileFullPath = path.resolve(root, targetFilePath);
@@ -119,7 +144,7 @@ async function buildDepTreeFromFiles(
     throw new Error(`Target file package.json not found at location: ${targetFileFullPath}`);
   }
   if (!fs.existsSync(lockFileFullPath)) {
-    throw new Error(`LockFile package-lock.json not found at location: ${lockFileFullPath}`);
+    throw new Error(`Lockfile package-lock.json not found at location: ${lockFileFullPath}`);
   }
 
   const targetFile = fs.readFileSync(targetFileFullPath, 'utf-8');