refactor: use map instead of object for internal cache

Author: mjeanroy

src/license-plugin.js

@@ -112,7 +112,7 @@ class LicensePlugin {
     // This is a cache storing a directory path to associated package.
     // This is an improvement to avoid looking for package information for
     // already scanned directory.
-    this._cache = {};
+    this._cache = new Map();
   }
 
   /**
@@ -160,8 +160,8 @@ class LicensePlugin {
 
     while (dir && dir !== this._cwd && !scannedDirs.includes(dir)) {
       // Try the cache.
-      if (_.has(this._cache, dir)) {
-        pkg = this._cache[dir];
+      if (this._cache.has(dir)) {
+        pkg = this._cache.get(dir);
         if (pkg) {
           this.debug(`found package.json in cache (package: ${pkg.name})`);
           this.addDependency(pkg);
@@ -222,7 +222,7 @@ class LicensePlugin {
 
     // Update the cache
     scannedDirs.forEach((scannedDir) => {
-      this._cache[scannedDir] = pkg;
+      this._cache.set(scannedDir, pkg);
     });
   }
 

test/license-plugin.spec.js

@@ -330,10 +330,9 @@ describe('LicensePlugin', () => {
         'fake-package': fakePackage,
       });
 
-      expect(plugin._cache).toEqual({
-        [path.join(__dirname, 'fixtures', 'fake-package-1', 'src')]: pkg,
-        [path.join(__dirname, 'fixtures', 'fake-package-1')]: pkg,
-      });
+      expect(plugin._cache.size).toBe(2);
+      expect(plugin._cache.get(path.join(__dirname, 'fixtures', 'fake-package-1', 'src'))).toEqual(pkg);
+      expect(plugin._cache.get(path.join(__dirname, 'fixtures', 'fake-package-1'))).toEqual(pkg);
     });
 
     it('should load pkg and put null without package', () => {
@@ -342,9 +341,8 @@ describe('LicensePlugin', () => {
       plugin.scanDependency(id);
 
       expect(plugin._dependencies).toEqual({});
-      expect(plugin._cache).toEqual({
-        [path.normalize(path.join(__dirname, '..', 'src'))]: null,
-      });
+      expect(plugin._cache.size).toBe(1);
+      expect(plugin._cache.get(path.normalize(path.join(__dirname, '..', 'src')))).toBeNull();
     });
 
     it('should try to load pkg without leading NULL character ', () => {
@@ -359,19 +357,18 @@ describe('LicensePlugin', () => {
         'fake-package': fakePackage,
       });
 
-      expect(plugin._cache).toEqual({
-        [path.join(__dirname, 'fixtures', 'fake-package-1', 'src')]: pkg,
-        [path.join(__dirname, 'fixtures', 'fake-package-1')]: pkg,
-      });
+      expect(plugin._cache.size).toBe(2);
+      expect(plugin._cache.get(path.join(__dirname, 'fixtures', 'fake-package-1', 'src'))).toEqual(pkg);
+      expect(plugin._cache.get(path.join(__dirname, 'fixtures', 'fake-package-1'))).toEqual(pkg);
     });
 
     it('should load pkg and use the cache if available', () => {
       const existsSync = spyOn(fs, 'existsSync').and.callThrough();
       const pkgPath = path.join(__dirname, 'fixtures', 'fake-package-1');
       const id = path.join(pkgPath, 'src', 'index.js');
 
-      plugin._cache[path.join(pkgPath, 'src')] = null;
-      plugin._cache[pkgPath] = null;
+      plugin._cache.set(path.join(pkgPath, 'src'), null);
+      plugin._cache.set(pkgPath, null);
 
       plugin.scanDependency(id);