add readme

README.md

@@ -0,0 +1,47 @@
+# zenstruck/memoize
+
+Helper trait to efficiently cache expensive methods in memory.
+
+## Installation
+
+```bash
+composer require zenstruck/memoize
+```
+
+## Usage
+
+Add the memoize trait to an object you wish to cache operations on.
+
+```php
+use Zenstruck\Memoize;
+
+class MyObject
+{
+    use Memoize;
+
+    public function method1(): mixed
+    {
+        return $this->memoize(
+            __FUNCTION__, // memoize requires a "cache key" an easy choice is the function name
+            fn() => $this->someExpensiveOperation() // called only the first time method1() is called
+        );
+    }
+
+    public function method2(string $parameter): mixed
+    {
+        return $this->memoize(
+            __FUNCTION__.$parameter, // cache key includes the parameter
+            fn() => $this->someExpensiveOperation($parameter) // called once per unique parameter
+        )
+    }
+
+    public function refresh(): void
+    {
+        $this->clearMemoized(); // clear all cached values for this object instance
+        $this->clearMemoized('method1'); // clear just the cached value for "method1"
+    }
+}
+```
+
+> **Note**: The cached values are stored in a `WeakMap` keyed by each object's instance. They are
+> automatically cleared as the objects are garbage collected.