From 7bb5865b70108024e0c4bef7197d2cfbab0f4061 Mon Sep 17 00:00:00 2001
From: atomiks <cc.glows@gmail.com>
Date: Sun, 31 Dec 2017 22:55:55 +1100
Subject: [PATCH] Add memoize snippet

---
 snippets/memoize.md | 23 +++++++++++++++++++++++
 tag_database        |  1 +
 2 files changed, 24 insertions(+)
 create mode 100644 snippets/memoize.md

diff --git a/snippets/memoize.md b/snippets/memoize.md
new file mode 100644
index 000000000..8a71702e1
--- /dev/null
+++ b/snippets/memoize.md
@@ -0,0 +1,23 @@
+### memoize
+
+Returns the memoized (cached) function.
+
+Use `Object.create(null)` to create an empty object without Object.prototype
+(so that those properties are not resolved if the input value is something like 'hasOwnProperty').
+Return a function which takes a single argument to be supplied to the memoized function
+by first checking if the function's output for that specific input value is already cached, or
+store and return it if not.
+
+```js
+const memoize = fn => {
+  const cache = Object.create(null);
+  return value => cache[value] || (cache[value] = fn(value));
+};
+```
+
+```js
+// See the `anagrams` snippet.
+const anagramsCached = memoize(anagrams);
+anagramsCached('javascript'); // takes a long time
+anagramsCached('javascript'); // returns virtually instantly since it's now cached
+```
diff --git a/tag_database b/tag_database
index d897e319c..f82dd92c5 100644
--- a/tag_database
+++ b/tag_database
@@ -81,6 +81,7 @@ lowercaseKeys:object
 mapObject:array
 max:math
 median:math
+memoize:function
 min:math
 negate:logic
 nthElement:array