@stdlib/string-starts-with

<details> <summary> About stdlib... </summary> <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> <p>The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.</p> <p>When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.</p> <p>To join us in bringing numerical computing to the web, get started by checking us out on <a href="https://github.com/stdlib-js/stdlib">GitHub</a>, and please consider <a href="https://opencollective.com/stdlib">financially supporting stdlib</a>. We greatly appreciate your continued support!</p> </details> # startsWith [![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]  > Test if a string starts with the characters of another string. <section class="intro"> </section>  <section class="installation"> ## Installation ```bash npm install @stdlib/string-starts-with ``` </section> <section class="usage"> ## Usage ```javascript var startsWith = require( '@stdlib/string-starts-with' ); ``` #### startsWith( str, search\[, position] ) Tests if a string starts with the characters of another string. ```javascript var str = 'To be, or not to be, that is the question.'; var bool = startsWith( str, 'To be' ); // returns true bool = startsWith( str, 'to be' ); // returns false ``` By default, the function searches from the beginning of the input string. To search from a different character index, provide a `position` value (zero-based). If provided a negative `position`, the start index is determined relative to the string end (i.e., `pos = str.length + position`). ```javascript var str = 'Remember the story I used to tell you when you were a boy?'; var bool = startsWith( str, 'the story' ); // returns false bool = startsWith( str, 'the story', 9 ); // returns true bool = startsWith( str, 'you', -15 ); // returns true ``` If provided an empty `search` string, the function **always** returns `true`. ```javascript var str = 'beep boop'; var bool = startsWith( str, '' ); // returns true ``` </section>  <section class="notes"> ## Notes - This function differs from [`String.prototype.startsWith`][mdn-string-startswith] in the following ways: - The function requires string values for the first and second arguments and requires that the `position` argument be an integer value. - The function does **not** clamp negative `position` values. Instead, when provided a negative `position`, the function resolves the starting search position relative to the end of the string. - Except when provided an empty `search` string, the function **always** returns `false` if a `position` resolves to a starting search position which exceeds the bounds of the input string. </section>  <section class="examples"> ## Examples  ```javascript var startsWith = require( '@stdlib/string-starts-with' ); var str = 'Fair is foul, and foul is fair, hover through fog and filthy air'; var bool = startsWith( str, 'Fair' ); // returns true bool = startsWith( str, 'fair' ); // returns false bool = startsWith( str, 'foul', 8 ); // returns true bool = startsWith( str, 'filthy', -10 ); // returns true ``` </section>   <section class="related"> ## See Also - <span class="package-name">[`@stdlib/string-starts-with-cli`][@stdlib/string-starts-with-cli]</span><span class="delimiter">: </span><span class="description">CLI package for use as a command-line utility.</span> - <span class="package-name">[`@stdlib/string-ends-with`][@stdlib/string/ends-with]</span><span class="delimiter">: </span><span class="description">test if a string ends with the characters of another string.</span> </section>   <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 © 2016-2024. The Stdlib [Authors][stdlib-authors]. </section>   <section class="links"> [@stdlib/string-starts-with-cli]: https://www.npmjs.com/package/@stdlib/string-starts-with-cli [npm-image]: http://img.shields.io/npm/v/@stdlib/string-starts-with.svg [npm-url]: https://npmjs.org/package/@stdlib/string-starts-with [test-image]: https://github.com/stdlib-js/string-starts-with/actions/workflows/test.yml/badge.svg?branch=v0.2.2 [test-url]: https://github.com/stdlib-js/string-starts-with/actions/workflows/test.yml?query=branch:v0.2.2 [coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/string-starts-with/main.svg [coverage-url]: https://codecov.io/github/stdlib-js/string-starts-with?branch=main  [chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg [chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im [stdlib]: https://github.com/stdlib-js/stdlib [stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors [cli-section]: https://github.com/stdlib-js/string-starts-with#cli [cli-url]: https://github.com/stdlib-js/string-starts-with/tree/cli [@stdlib/string-starts-with]: https://github.com/stdlib-js/string-starts-with/tree/main [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/string-starts-with/tree/deno [deno-readme]: https://github.com/stdlib-js/string-starts-with/blob/deno/README.md [umd-url]: https://github.com/stdlib-js/string-starts-with/tree/umd [umd-readme]: https://github.com/stdlib-js/string-starts-with/blob/umd/README.md [esm-url]: https://github.com/stdlib-js/string-starts-with/tree/esm [esm-readme]: https://github.com/stdlib-js/string-starts-with/blob/esm/README.md [branches-url]: https://github.com/stdlib-js/string-starts-with/blob/main/branches.md [stdlib-license]: https://raw.githubusercontent.com/stdlib-js/string-starts-with/main/LICENSE [standard-streams]: https://en.wikipedia.org/wiki/Standard_streams [mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions [mdn-string-startswith]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith  [@stdlib/string/ends-with]: https://www.npmjs.com/package/@stdlib/string-ends-with  </section>