npm package: @stdlib/utils-timeit-cli
Description: Time a snippet.
Author: The Stdlib Authors
Latest version: 0.2.4

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  <summary>
    About stdlib...
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  <p>We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.</p>
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</details>

# timeit

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

> Time a snippet.

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<section class="intro">

</section>

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<section class="cli">



<section class="installation">

## Installation

To use as a general utility, install the CLI package globally

```bash
npm install -g @stdlib/utils-timeit-cli
```

</section>
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<section class="usage">

## Usage

```text
Usage: timeit [options] [<code>]

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
         --iterations iter     Number of iterations.
         --repeats repeats     Number of repeats. Default: 3.
         --before setup        Setup code.
         --after cleanup       Cleanup code.
         --async               Time asynchronous code.
         --format fmt          Output format: pretty, csv, json. Default: pretty.
```

</section>

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<section class="notes">

## Notes

-   When the output format is `csv`, the output consists of **only** raw timing results.
-   If not explicitly provided `--iterations`, the implementation tries successive powers of `10` until the total time is at least `0.1` seconds.

</section>

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<section class="examples">

## Examples

```bash
$ timeit "$(cat ./examples/code.txt)" --before "$(cat ./examples/before.txt)" --iterations 1000000

iterations: 1000000
repeats: 3
iterations/s: 7261975.851461222
elapsed time: 0.13770357 sec
lower bound: 0.13770357 usec/iteration
```

To output results as JSON,

```bash
$ timeit "$(cat ./examples/code.txt)" --before "$(cat ./examples/before.txt)" --iterations 1000000 --format json
{"iterations":1000000,"repeats":3,"min":[0,132431806],"elapsed":0.132431806,"rate":7551056.1261997735,"times":[[0,142115140],[0,132431806],[0,134808376]]}
```

To output results as comma-separated values ([CSV][csv]),

```bash
$ timeit "$(cat ./examples/code.txt)" --before "$(cat ./examples/before.txt)" --iterations 1000000 --format csv
seconds,nanoseconds
0,139365407
0,138033545
0,135175834
```

To use as part of a pipeline,

```bash
$ cat ./examples/code.txt | timeit --before "$(cat ./examples/before.txt)" --iterations 1000000

iterations: 1000000
repeats: 3
iterations/s: 7433536.674260073
elapsed time: 0.134525468 sec
lower bound: 0.134525468 usec/iteration
```

</section>

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</section>

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* * *

<section class="references">

## References

-   Chen, Jiahao, and Jarrett Revels. 2016. "Robust benchmarking in noisy environments." _CoRR_ abs/1608.04295 (August). <http://arxiv.org/abs/1608.04295>.

</section>

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<section class="related">

## See Also

-   <span class="package-name">[`@stdlib/utils-timeit`][@stdlib/utils-timeit]</span><span class="delimiter">: </span><span class="description">time a snippet.</span>


</section>

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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].

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