feat. add has method

.github/workflows/test.yml

@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [12.x, 14.x, 15.x]
+        node-version: [12.x, 14.x, 16.x]
         # See supported Node.js release schedule at https://nodejs.org/en/about/releases/
     env:
       MYSQL_DB_DATABASE: keyv_test

packages/keyv-test-suite/src/api.js

@@ -101,6 +101,22 @@ const keyvApiTests = (test, Keyv, store) => {
 		t.is(await keyv.get('fizz'), undefined);
 	});
 
+	test.serial('.has(key) returns a Promise', t => {
+		const keyv = new Keyv({ store: store() });
+		t.true(keyv.has('foo') instanceof Promise);
+	});
+
+	test.serial('.has(key) resolves to true', async t => {
+		const keyv = new Keyv({ store: store() });
+		await keyv.set('foo', 'bar');
+		t.is(await keyv.has('foo'), true);
+	});
+
+	test.serial('.has(key) with nonexistent key resolves to false', async t => {
+		const keyv = new Keyv({ store: store() });
+		t.is(await keyv.has('foo'), false);
+	});
+
 	test.after.always(async () => {
 		const keyv = new Keyv({ store: store() });
 		await keyv.clear();

packages/keyv/src/index.js

@@ -15,11 +15,7 @@ class Keyv extends EventEmitter {
 			options
 		);
 
-		this.store = this.options.store;
-
-		if (!this.store) {
-			this.store = new Map();
-		}
+		this.store = this.options.store || new Map();
 
 		this.store.namespace = this.options.namespace;
 
@@ -83,6 +79,19 @@ class Keyv extends EventEmitter {
 			});
 	}
 
+	has(key) {
+		const keyPrefixed = this._getKeyPrefix(key);
+		const store = this.store;
+		if (typeof store.has === 'function') {
+			return Promise.resolve()
+				.then(() => store.has(keyPrefixed));
+		}
+
+		return Promise.resolve()
+			.then(() => store.get(keyPrefixed))
+			.then(data => data !== undefined);
+	}
+
 	set(key, value, ttl) {
 		const keyPrefixed = this._getKeyPrefix(key);
 		if (typeof ttl === 'undefined') {