# Define Memoized Property
> [Define][mdn-define-property] a memoized object property.
## Usage
```javascript
var defineMemoizedProperty = require( '@stdlib/utils/define-memoized-property' );
```
#### defineMemoizedProperty( obj, prop, descriptor )
[Defines][mdn-define-property] a memoized object property.
```javascript
var obj = {};
function foo() {
return 'bar';
}
defineMemoizedProperty( obj, 'foo', {
'configurable': false,
'enumerable': true,
'writable': false,
'value': foo
});
var v = obj.foo;
// returns 'bar'
```
A property `descriptor` has the following required properties:
- **value**: synchronous function whose return value will be memoized and set as the property value.
A property `descriptor` has the following optional properties:
- **configurable**: `boolean` indicating if property descriptor can be changed and if the property can be deleted from the provided object. Default: `false`.
- **enumerable**: `boolean` indicating if the property shows up when enumerating object properties. Default: `false`.
- **writable**: `boolean` indicating if the value associated with the property can be changed with an assignment operator. Default: `false`.
## Notes
- Until deferred evaluation, an object property is **configurable**.
## Examples
```javascript
var fibonacci = require( '@stdlib/math/base/special/fibonacci' );
var defineMemoizedProperty = require( '@stdlib/utils/define-memoized-property' );
function Foo() {
var self;
if ( !(this instanceof Foo) ) {
return new Foo();
}
self = this;
this.count = 0;
defineMemoizedProperty( this, 'fibo', {
'value': fibo
});
return this;
function fibo() {
self.count += 1;
return fibonacci( 73 );
}
}
var foo = new Foo();
var i;
for ( i = 0; i < 10; i++ ) {
console.log( 'F: %d. Count: %d.', foo.fibo, foo.count );
}
```
[mdn-define-property]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty