Add pMemoize.clear() method

Closes #1

.gitattributes

@@ -1,2 +1 @@
-* text=auto
-*.js text eol=lf
+* text=auto eol=lf

.gitignore

@@ -1 +1,2 @@
 node_modules
+yarn.lock

index.js

@@ -2,17 +2,21 @@
 const mem = require('mem');
 const mimicFn = require('mimic-fn');
 
+const memoizedFns = new WeakMap();
+
 module.exports = (fn, opts) => {
 	const memoized = mem(fn, opts);
 
 	const ret = function (...args) {
-		return memoized.apply(this, args).catch(err => {
-			mem.clear(memoized);
-			throw err;
-		});
+		return memoized.apply(this, args);
 	};
 
 	mimicFn(ret, fn);
+	memoizedFns.set(ret, memoized);
 
 	return ret;
 };
+
+module.exports.clear = fn => {
+	mem.clear(memoizedFns.get(fn));
+};

package.json

@@ -39,7 +39,7 @@
 		"bluebird"
 	],
 	"dependencies": {
-		"mem": "^1.1.0",
+		"mem": "^3.0.0",
 		"mimic-fn": "^1.0.0"
 	},
 	"devDependencies": {

readme.md

@@ -8,7 +8,7 @@ Useful for speeding up consecutive function calls by caching the result of calls
 ## Install
 
 ```
-$ npm install --save p-memoize
+$ npm install p-memoize
 ```
 
 
@@ -19,23 +19,41 @@ const pMemoize = require('p-memoize');
 const got = require('got');
 const memGot = pMemoize(got, {maxAge: 1000});
 
-memGot('sindresorhus.com').then(() => {
-	// this call is cached
-	memGot('sindresorhus.com').then(() => {
-		setTimeout(() => {
-			// this call is not cached as the cache has expired
-			memGot('sindresorhus.com').then(() => {});
-		}, 2000);
-	});
-});
+(async () => {
+	memGot('sindresorhus.com');
+
+	// This call is cached
+	memGot('sindresorhus.com');
+
+	setTimeout(() => {
+		// This call is not cached as the cache has expired
+		memGot('sindresorhus.com');
+	}, 2000);
+})();
 ```
 
 
 ## API
 
-See the [`mem` docs](https://github.com/sindresorhus/mem#api).
+### pMemoize(input, [options])
+
+Returns a memoized version of the `input` function.
+
+#### input
+
+Type: `Function`
+
+Promise-returning or async function to be memoized.
+
+#### options
+
+Type: `Object`
+
+See the [`mem` options](https://github.com/sindresorhus/mem#options).
+
+### pMemoize.clear(fn)
 
-The only difference is that this module does not cache rejected promises.
+Clear all cached data of a memoized function.
 
 
 ## Related

test.js

@@ -36,3 +36,14 @@ test('does not memoize rejected promise', async t => {
 test('preserves the original function name', t => {
 	t.is(m(async function foo() {}).name, 'foo'); // eslint-disable-line func-names, prefer-arrow-callback
 });
+
+test('pMemoize.clear()', t => {
+	let i = 0;
+	const f = () => i++;
+	const memoized = m(f);
+	t.is(memoized(), 0);
+	t.is(memoized(), 0);
+	m.clear(memoized);
+	t.is(memoized(), 1);
+	t.is(memoized(), 1);
+});