Add per file listener for caching. (#1242)

lib/util/storage.js

@@ -40,6 +40,7 @@ const proxyHandler = {
  * @param {Object} [options] Storage options.
  * @param {Boolean} [options.lodashPath=false] Set true to treat name as a lodash path.
  * @param {Boolean} [options.disableCache=false] Set true to disable json object cache.
+ * @param {Boolean} [options.disableCacheByFile=false] Set true to cleanup cache for every fs change.
  *
  * @example
  * class extend Generator {
@@ -62,20 +63,28 @@ class Storage {
 
     _.defaults(options, {
       lodash: false,
-      disableCache: false
+      disableCache: false,
+      disableCacheByFile: false
     });
 
     assert(configPath, 'A config filepath is required to create a storage');
 
     this.path = configPath;
     this.name = name;
     this.fs = fs;
-    this.existed = Object.keys(this._store).length > 0;
     this.indent = 2;
     this.lodashPath = options.lodashPath;
     this.disableCache = options.disableCache;
+    this.disableCacheByFile = options.disableCacheByFile;
+
+    this.existed = Object.keys(this._store).length > 0;
+
+    this.fs.store.on('change', filename => {
+      // At mem-fs 1.1.3 filename is not passed to the event.
+      if (this.disableCacheByFile || (filename && filename !== this.path)) {
+        return;
+      }
 
-    this.fs.store.on('change', () => {
       delete this._cachedStore;
     });
   }

package.json

@@ -31,7 +31,7 @@
     "inquirer": "^6.3.1",
     "jsdoc": "^3.6.3",
     "lint-staged": "^8.1.7",
-    "mem-fs": "^1.1.3",
+    "mem-fs": "^1.2.0",
     "mocha": "^7.1.1",
     "mockery": "^2.1.0",
     "nock": "^12.0.3",

test/storage.js

@@ -335,4 +335,45 @@ describe('Storage', () => {
       assert.deepStrictEqual({ ...proxy }, { foo: 'bar', john: 'doe' });
     });
   });
+
+  describe('caching', () => {
+    beforeEach(function() {
+      // Make sure the cache is loaded.
+      // on instantiation a change event is emitted when the file loads to mem-fs
+      this.store.get('foo');
+    });
+
+    it('loads', function() {
+      assert(this.store._cachedStore);
+    });
+
+    it("doesn't loads when disabled", function() {
+      const store = new Storage('test', this.fs, this.storePath, { disableCache: true });
+      assert(store._cachedStore === undefined);
+      store.get('foo');
+      assert(store._cachedStore === undefined);
+    });
+
+    it('cleanups when the file changes', function() {
+      this.fs.writeJSON(this.store.path, {});
+      assert(this.store._cachedStore === undefined);
+    });
+
+    it("doesn't cleanup when another file changes", function() {
+      this.fs.write('a.txt', 'anything');
+      assert(this.store._cachedStore);
+    });
+
+    it('cleanups when per file cache is disabled and another file changes', function() {
+      this.fs.writeJSON(this.store.path, { disableCacheByFile: true });
+      this.fs.write('a.txt', 'anything');
+      assert(this.store._cachedStore === undefined);
+    });
+
+    // Compatibility for mem-fs <= 1.1.3
+    it('cleanups when change event argument is undefined', function() {
+      this.memFs.emit('change');
+      assert(this.store._cachedStore === undefined);
+    });
+  });
 });