Add memoize functor methods

PR-URL: #284

lib/memoize.js

@@ -28,7 +28,8 @@ const memoize = (
     timeout: 0,
     limit: 0,
     size: 0,
-    maxSize: 0
+    maxSize: 0,
+    maxCount: 0,
   };
 
   Object.setPrototypeOf(memoized, Memoized.prototype);
@@ -39,6 +40,22 @@ Memoized.prototype.clear = function() {
   this.cache.clear();
 };
 
+Memoized.prototype.add = function(key, err, data) {
+  this.cache.set(key, { err, data });
+  return this;
+};
+
+Memoized.prototype.del = function(key) {
+  this.cache.delete(key);
+  return this;
+};
+
+Memoized.prototype.get = function(key, callback) {
+  const record = this.cache.get(key);
+  callback(record.err, record.data);
+  return this;
+};
+
 module.exports = {
   memoize,
 };

test/memoize.js

@@ -65,3 +65,69 @@ tap.test('memoize clear cache', (test) => {
     });
   });
 });
+
+tap.test('memoize cache del', (test) => {
+  const storage = {
+    file1: Buffer.from('file1'),
+  };
+
+  const getData = (file, callback) => {
+    process.nextTick(() => {
+      const result = storage[file];
+      if (result) callback(null, result);
+      else callback(new Error('File not found'));
+    });
+  };
+
+  const memoizedGetData = metasync.memoize(getData);
+
+  memoizedGetData('file1', (err, data) => {
+    test.error(err);
+    test.strictSame(data, storage.file1);
+    storage.file1 = Buffer.from('changed');
+    memoizedGetData.del('file1');
+    memoizedGetData('file1', (err, data) => {
+      test.error(err);
+      test.strictSame(data, Buffer.from('changed'));
+      test.end();
+    });
+  });
+});
+
+tap.test('memoize cache add', (test) => {
+  const getData = (file, callback) => {
+    process.nextTick(() => {
+      const result = Buffer.from('added');
+      callback(null, result);
+    });
+  };
+
+  const memoizedGetData = metasync.memoize(getData);
+
+  const file1 = Buffer.from('added');
+  memoizedGetData.add('file1', null, file1);
+  memoizedGetData('file1', (err, data) => {
+    test.error(err);
+    test.strictSame(data, Buffer.from('added'));
+    test.end();
+  });
+});
+
+tap.test('memoize cache get', (test) => {
+  const getData = (file, callback) => {
+    process.nextTick(() => {
+      const result = Buffer.from('added');
+      callback(null, result);
+    });
+  };
+
+  const memoizedGetData = metasync.memoize(getData);
+
+  const file1 = Buffer.from('added');
+  memoizedGetData.add('file1', null, file1);
+  memoizedGetData.get('file1', (err, data) => {
+    test.error(err);
+    test.strictSame(data, Buffer.from('added'));
+    test.end();
+  });
+});