https://github.com/stdlib-js/string-substring-before
Return the part of a string before a specified substring.
https://github.com/stdlib-js/string-substring-before
before check javascript match node node-js nodejs search stdlib str string substr substring util utilities utility utils
Last synced: 7 months ago
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Return the part of a string before a specified substring.
- Host: GitHub
- URL: https://github.com/stdlib-js/string-substring-before
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-09-18T17:56:09.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2024-12-01T03:28:50.000Z (about 1 year ago)
- Last Synced: 2025-05-03T09:49:22.498Z (8 months ago)
- Topics: before, check, javascript, match, node, node-js, nodejs, search, stdlib, str, string, substr, substring, util, utilities, utility, utils
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 804 KB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
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# substringBefore
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Return the part of a string before a specified substring.
## Installation
```bash
npm install @stdlib/string-substring-before
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
- To use as a general utility for the command line, install the corresponding [CLI package][cli-section] globally.
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var substringBefore = require( '@stdlib/string-substring-before' );
```
#### substringBefore( str, search )
Returns the part of a string before a specified substring.
```javascript
var str = 'beep boop';
var out = substringBefore( str, ' ' );
// returns 'beep'
out = substringBefore( str, 'o' );
// returns 'beep b'
```
## Notes
- If a substring is not present in a provided string, the function returns the input string.
- If provided an empty substring, the function returns an empty string.
## Examples
```javascript
var substringBefore = require( '@stdlib/string-substring-before' );
var out = substringBefore( 'beep boop', 'p' );
// returns 'bee'
out = substringBefore( 'Hello World!', 'xyz' );
// returns 'Hello World!'
out = substringBefore( 'Hello World!', '' );
// returns ''
out = substringBefore( '', 'xyz' );
// returns ''
```
* * *
## CLI
## Installation
To use as a general utility, install the CLI package globally
```bash
npm install -g @stdlib/string-substring-before-cli
```
### Usage
```text
Usage: substring-before [options] --search= []
Options:
-h, --help Print this message.
-V, --version Print the package version.
--search string Search string.
--split sep Delimiter for stdin data. Default: '/\\r?\\n/'.
```
### Notes
- If the split separator is a [regular expression][mdn-regexp], ensure that the `split` option is either properly escaped or enclosed in quotes.
```bash
# Not escaped...
$ echo -n $'foo\nbar\nbaz' | substring-before --search a --split /\r?\n/
# Escaped...
$ echo -n $'foo\nbar\nbaz' | substring-before --search a --split /\\r?\\n/
```
- The implementation ignores trailing delimiters.
### Examples
```bash
$ substring-before abcdefg --search d
abc
```
To use as a [standard stream][standard-streams],
```bash
$ echo -n $'beep\nboop' | substring-before --search p
bee
boo
```
By default, when used as a [standard stream][standard-streams], the implementation assumes newline-delimited data. To specify an alternative delimiter, set the `split` option.
```bash
$ echo -n 'beep\tboop' | substring-before --search p --split '\t'
bee
boo
```
* * *
## See Also
- [`@stdlib/string-substring-before-last`][@stdlib/string/substring-before-last]: return the part of a string before the last occurrence of a specified substring.
- [`@stdlib/string-substring-after`][@stdlib/string/substring-after]: return the part of a string after a specified substring.
- [`@stdlib/string-substring-after-last`][@stdlib/string/substring-after-last]: return the part of a string after the last occurrence of a specified substring.
* * *
## 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].
[npm-image]: http://img.shields.io/npm/v/@stdlib/string-substring-before.svg
[npm-url]: https://npmjs.org/package/@stdlib/string-substring-before
[test-image]: https://github.com/stdlib-js/string-substring-before/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/string-substring-before/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/string-substring-before/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/string-substring-before?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-substring-before#cli
[cli-url]: https://github.com/stdlib-js/string-substring-before/tree/cli
[@stdlib/string-substring-before]: https://github.com/stdlib-js/string-substring-before/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-substring-before/tree/deno
[deno-readme]: https://github.com/stdlib-js/string-substring-before/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/string-substring-before/tree/umd
[umd-readme]: https://github.com/stdlib-js/string-substring-before/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/string-substring-before/tree/esm
[esm-readme]: https://github.com/stdlib-js/string-substring-before/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/string-substring-before/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/string-substring-before/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
[@stdlib/string/substring-before-last]: https://github.com/stdlib-js/string-substring-before-last
[@stdlib/string/substring-after]: https://github.com/stdlib-js/string-substring-after
[@stdlib/string/substring-after-last]: https://github.com/stdlib-js/string-substring-after-last