npm package: @stdlib/utils-define-memoized-read-only-property
Description: Define a memoized read-only object property.
Author: The Stdlib Authors
Latest version: 0.2.3

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# Memoized Read-Only

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> [Define][mdn-define-property] a memoized **read-only** object property.

<section class="installation">

## Installation

```bash
npm install @stdlib/utils-define-memoized-read-only-property
```

</section>

<section class="usage">

## 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.

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   A **read-only** property is **enumerable** and **non-configurable**; however, until deferred evaluation, an object property is **configurable**.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```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 );
}
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/utils-define-memoized-property`][@stdlib/utils/define-memoized-property]</span><span class="delimiter">: </span><span class="description">define a memoized object property.</span>
-   <span class="package-name">[`@stdlib/utils-define-read-only-property`][@stdlib/utils/define-read-only-property]</span><span class="delimiter">: </span><span class="description">define a read-only property.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

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[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-define-memoized-read-only-property/main.svg
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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/utils-define-memoized-read-only-property/tree/deno
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-define-memoized-read-only-property/main/LICENSE

[mdn-define-property]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty

<!-- <related-links> -->

[@stdlib/utils/define-memoized-property]: https://www.npmjs.com/package/@stdlib/utils-define-memoized-property

[@stdlib/utils/define-read-only-property]: https://www.npmjs.com/package/@stdlib/utils-define-read-only-property

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</section>

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