# isDigitString
> Test whether a string contains only numeric digits.
## Usage
```javascript
var isDigitString = require( '@stdlib/assert/is-digit-string' );
```
#### isDigitString( value )
Tests whether a string contains only numeric digits.
```javascript
var bool = isDigitString( '0123456789' );
// returns true
```
## Notes
- For non-string values, the function returns `false`.
## Examples
```javascript
var isDigitString = require( '@stdlib/assert/is-digit-string' );
var out = isDigitString( '0123456789' );
// returns true
out = isDigitString( '' );
// returns false
out = isDigitString( '0xffffff' );
// returns false
out = isDigitString( 123 );
// returns false
```
* * *
## CLI
### Usage
```text
Usage: is-digit-string [options] []
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][mdn-regexp], ensure that the `split` option is either properly escaped or enclosed in quotes.
```bash
# Not escaped...
$ echo -n $'beEp booP\n0123456' | is-digit-string --split /\r?\n/
# Escaped...
$ echo -n $'beEp booP\n0123456' | is-digit-string --split /\\r?\\n/
```
- The implementation ignores trailing delimiters.
### Examples
```bash
$ is-digit-string 0123456789
true
```
To use as a [standard stream][standard-streams],
```bash
$ echo -n '0123456789' | is-digit-string
true
```
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\t123' | is-digit-string --split '\t'
false
true
```
[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams
[mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
[@stdlib/assert/is-hex-string]: https://github.com/stdlib-js/assert/tree/main/is-hex-string
[@stdlib/assert/is-string]: https://github.com/stdlib-js/assert/tree/main/is-string