@stdlib/string-starts-with

Test if a string starts with the characters of another string.


Keywords
stdlib, stdstring, utilities, utility, utils, util, string, str, check, begins, begin, starts, start, test, search, match, javascript, node, node-js, nodejs
License
Apache-2.0
Install
npm install @stdlib/string-starts-with@0.0.7

Documentation

startsWith

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Test if a string starts with the characters of another string.

Installation

npm install @stdlib/string-starts-with

Usage

var startsWith = require( '@stdlib/string-starts-with' );

startsWith( str, search[, position] )

Tests if a string starts with the characters of another string.

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 (pos = str.length + position).

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.

var str = 'beep boop';

var bool = startsWith( str, '' );
// returns true

Examples

var startsWith = require( '@stdlib/string-starts-with' );

var bool;
var str;

str = 'Fair is foul, and foul is fair, hover through fog and filthy air';

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

CLI

Installation

To use the module as a general utility, install the module globally

npm install -g @stdlib/string-starts-with

Usage

Usage: starts-with [options] --search=<string> [<string>]

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
         --search string       Search string.
         --pos int             Search position.

Examples

$ starts-with --search=be beep
true

To use as a standard stream,

$ echo -n 'boop' | starts-with --search=bo
true

Notice

This package is part of 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, see the main project repository.

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License

See LICENSE.

Copyright

Copyright © 2016-2021. The Stdlib Authors.