From cd6320aa625e98ce0fd591af376c23be3f2d21fa Mon Sep 17 00:00:00 2001
From: Keith Cirkel <keithamus@users.noreply.github.com>
Date: Wed, 20 Jun 2018 07:36:14 +0100
Subject: [PATCH] Delete cache entries older than max age (#16)

---
 index.js |  2 ++
 test.js  | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/index.js b/index.js
index ad49270..42dc788 100644
--- a/index.js
+++ b/index.js
@@ -29,6 +29,8 @@ module.exports = (fn, opts) => {
 			if (typeof opts.maxAge !== 'number' || Date.now() < c.maxAge) {
 				return c.data;
 			}
+
+			cache.delete(key);
 		}
 
 		const ret = fn.apply(this, arguments);
diff --git a/test.js b/test.js
index d4b06d6..534e789 100644
--- a/test.js
+++ b/test.js
@@ -40,6 +40,45 @@ test('maxAge option', async t => {
 	t.is(memoized(1), 1);
 });
 
+test('maxAge option deletes old items', async t => {
+	let i = 0;
+	const f = () => i++;
+	const cache = new Map();
+	const deleted = [];
+	cache.delete = item => deleted.push(item);
+	const memoized = m(f, {maxAge: 100, cache});
+	t.is(memoized(1), 0);
+	t.is(memoized(1), 0);
+	t.is(cache.has(1), true);
+	await delay(50);
+	t.is(memoized(1), 0);
+	t.is(deleted.length, 0);
+	await delay(200);
+	t.is(memoized(1), 1);
+	t.is(deleted.length, 1);
+	t.is(deleted[0], 1);
+});
+
+test('maxAge items are deleted even if function throws', async t => {
+	let i = 0;
+	const f = () => {
+		if (i === 1) {
+			throw new Error('failure');
+		}
+		return i++;
+	};
+	const cache = new Map();
+	const memoized = m(f, {maxAge: 100, cache});
+	t.is(memoized(1), 0);
+	t.is(memoized(1), 0);
+	t.is(cache.size, 1);
+	await delay(50);
+	t.is(memoized(1), 0);
+	await delay(200);
+	t.throws(() => memoized(1), 'failure');
+	t.is(cache.size, 0);
+});
+
 test('cacheKey option', t => {
 	let i = 0;
 	const f = () => i++;