# Memoized Read-Only
> [Define][mdn-define-property] a memoized **read-only** object property.
## Usage
```javascript
var setMemoizedReadOnly = require( '@stdlib/utils/define-memoized-read-only-property' );
```
#### setMemoizedReadOnly( obj, prop, fcn )
[Defines][mdn-define-property] a memoized **read-only** object property.
```javascript
var obj = {};
function foo() {
return 'bar';
}
setMemoizedReadOnly( obj, 'foo', foo );
var v = obj.foo;
// returns 'bar'
```
The last argument should be a synchronous function whose return value will be memoized and set as the property value.
## Notes
- A **read-only** property is **enumerable** and **non-configurable**; however, until deferred evaluation, an object property is **configurable**.
## Examples
```javascript
var fibonacci = require( '@stdlib/math/base/special/fibonacci' );
var setMemoizedReadOnly = require( '@stdlib/utils/define-memoized-read-only-property' );
function Foo() {
var self;
if ( !(this instanceof Foo) ) {
return new Foo();
}
self = this;
this.count = 0;
setMemoizedReadOnly( this, 'fibo', 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