npm package: @stdlib/iter-constant
Description: Create an iterator which always returns the same value.
Author: The Stdlib Authors
Latest version: 0.2.3

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    About stdlib...
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# iterConstant

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

> Create an iterator which always returns the same value.

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/iter-constant
```

</section>

<section class="usage">

## Usage

```javascript
var iterConstant = require( '@stdlib/iter-constant' );
```

#### iterConstant( value\[, options] )

Returns an iterator which always returns the same value.

```javascript
var it = iterConstant( 3.14 );
// returns <Object>

var v = it.next().value;
// returns 3.14

v = it.next().value;
// returns 3.14

v = it.next().value;
// returns 3.14

// ...
```

The returned iterator protocol-compliant object has the following properties:

-   **next**: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a `value` property and a `done` property having a `boolean` value indicating whether the iterator is finished.
-   **return**: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

The function supports the following `options`:

-   **iter**: number of iterations. Default: `1e308`.

By default, the function returns an infinite iterator (i.e., an iterator which never ends). To limit the number of iterations, set the `iter` option.

```javascript
var opts = {
    'iter': 2
};
var it = iterConstant( 3.14, opts );
// returns <Object>

var v = it.next().value;
// returns 3.14

v = it.next().value;
// returns 3.14

var bool = it.next().done;
// returns true
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   When provided an `object` reference, the returned iterator always returns the same reference.

    ```javascript
    var arr = [ 1, 2, 3, 4 ];

    var it = iterConstant( arr );
    // returns <Object>

    var v1 = it.next().value;
    // returns [ 1, 2, 3, 4 ]

    var bool = ( v1 === arr );
    // returns true

    var v2 = it.next().value;
    // returns [ 1, 2, 3, 4 ]

    bool = ( v2 === arr );
    // returns true

    // ...
    ```

    To avoid unwanted `object` mutation, copy a provided `value` **before** creating an iterator.

-   If an environment supports `Symbol.iterator`, the returned iterator is iterable.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random-base-randu' );
var iterConstant = require( '@stdlib/iter-constant' );

// Create an iterator:
var opts = {
    'iter': 10
};
var it = iterConstant( randu(), opts );

// Perform manual iteration...
var v;
while ( true ) {
    v = it.next();
    if ( v.done ) {
        break;
    }
    console.log( v.value );
}
```

</section>

<!-- /.examples -->

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</section>

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<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/utils-constant-function`][@stdlib/utils/constant-function]</span><span class="delimiter">: </span><span class="description">constant function.</span>

</section>

<!-- /.related -->

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<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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[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/iter-constant/tree/deno
[deno-readme]: https://github.com/stdlib-js/iter-constant/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/iter-constant/tree/umd
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[@stdlib/utils/constant-function]: https://www.npmjs.com/package/@stdlib/utils-constant-function

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</section>

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