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stdlib-js/assert-is-blank-string

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isBlankString

NPM version Build Status Coverage Status

Test if a value is a blank string.

Installation

npm install @stdlib/assert-is-blank-string

Alternatively,

  • To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
  • If you are using Deno, visit the deno branch (see README for usage intructions).
  • For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).
  • To use as a general utility for the command line, install the corresponding CLI package globally.

The branches.md 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

var isBlankString = require( '@stdlib/assert-is-blank-string' );

isBlankString( value )

Tests if a value is a blank string (i.e., an empty string or a string consisting only of whitespace characters).

var bool = isBlankString( '   ' );
// returns true

bool = isBlankString( '' );
// returns true

bool = isBlankString( 0 );
// returns false

Examples

var isBlankString = require( '@stdlib/assert-is-blank-string' );

var out = isBlankString( '   ' );
// returns true

out = isBlankString( '\t\t\t' );
// returns true

out = isBlankString( '\r\n' );
// returns true

out = isBlankString( '' );
// returns true

out = isBlankString( 'beep boop' );
// returns false

out = isBlankString( null );
// returns false

CLI

Installation

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

npm install -g @stdlib/assert-is-blank-string-cli

Usage

Usage: is-blank-string [options] [<string>]

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
         --split sep           Delimiter for stdin data. Default: '/\\r?\\n/'.

Notes

  • If the split separator is a regular expression, ensure that the split option is either properly escaped or enclosed in quotes.

    # Not escaped...
    $ echo -n $'\nisMobile' | is-blank-string --split /\r?\n/
    # Escaped...
    $ echo -n $'\nisMobile' | is-blank-string --split /\\r?\\n/
  • The implementation ignores trailing delimiters.

Examples

$ is-blank-string baz
false

To use as a standard stream,

$ echo -n ' \t ' | is-blank-string
true

By default, when used as a standard stream, the implementation assumes newline-delimited data. To specify an alternative delimiter, set the split option.

$ echo -n '\t123' | is-blank-string --split '\t'
true
false

See Also


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 © 2016-2024. The Stdlib Authors.