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# printable-characters
[](https://travis-ci.org/xpl/printable-characters) [](https://coveralls.io/github/xpl/printable-characters) [](https://npmjs.com/package/printable-characters) [](https://scrutinizer-ci.com/g/xpl/printable-characters/?branch=master) [](https://david-dm.org/xpl/printable-characters)
A little helper for handling strings containing zero width characters, ANSI styling, whitespaces, newlines, [weird Unicode 💩 symbols](http://blog.jonnew.com/posts/poo-dot-length-equals-two), etc.
## Determining the real (visible) length of a string
```javascript
const { strlen } = require ('printable-characters')
strlen ('foo bar') // === 7
strlen ('\u001b[106mfoo bar\u001b[49m') // === 7
```
## Detecting blank text
```javascript
const { isBlank } = require ('printable-characters')
isBlank ('foobar') // === false
isBlank ('\u001b[106m \t \t \n \u001b[49m') // === true
```
## Obtaining a blank string of the same width
```javascript
const { blank } = require ('printable-characters')
blank ('💩') // === ' '
blank ('foo') // === ' '
blank ('\tfoo \nfoo') // === '\t \n '
blank ('\u001b[22m\u001b[1mfoo \t\u001b[39m\u001b[22m')) // === ' \t'
```
## Matching invisible characters
```javascript
const { ansiEscapeCodes, zeroWidthCharacters } = require ('printable-characters')
const s = '\u001b[106m' + 'foo' + '\n' + 'bar' + '\u001b[49m'
s.replace (ansiEscapeCodes, '') // === 'foo\nbar'
.replace (zeroWidthCharacters, '') // === 'foobar'
```
## Getting the first N visible symbols, preserving the invisible parts
Use for safely truncating strings to maximum width without breaking ANSI codes:
```javascript
const { first } = require ('printable-characters')
const s = '\u001b[22mfoobar\u001b[22m'
first (s, 0) // === '\u001b[22m\u001b[22m'
first (s, 1) // === '\u001b[22mf\u001b[22m'
first (s, 3) // === '\u001b[22mfoo\u001b[22m'
first (s, 6) // === '\u001b[22mfoobar\u001b[22m'
```
## Extracting the invisible parts followed by the visible ones (parsing)
```javascript
const { partition } = require ('printable-characters')
partition ('') // [ ])
partition ('foo') // [['', 'foo'] ])
partition ('\u001b[1mfoo') // [['\u001b[1m', 'foo'] ])
partition ('\u001b[1mfoo\u0000bar') // [['\u001b[1m', 'foo'], ['\u0000', 'bar'] ])
partition ('\u001b[1mfoo\u0000bar\n') // [['\u001b[1m', 'foo'], ['\u0000', 'bar'], ['\n', '']])
```
## Applications
- [as-table](https://github.com/xpl/as-table) — a simple function that prints objects as ASCII tables
- [string.bullet](https://github.com/xpl/string.bullet) — ASCII-mode bulleting for the list-style data
- [string.ify](https://github.com/xpl/string.ify) — a fancy pretty printer for the JavaScript entities
- [Ololog!](https://github.com/xpl/ololog) — a better `console.log` for the log-driven debugging junkies!
## TODO
Handle multi-component emojis, as in [this article](http://blog.jonnew.com/posts/poo-dot-length-equals-two):
```javascript
assert.equal (strlen ('👩❤️💋👩'), 1) // FAILING, see http://blog.jonnew.com/posts/poo-dot-length-equals-two for possible solution
assert.equal (blank ('👩❤️💋👩'), ' ') // FAILING, see http://blog.jonnew.com/posts/poo-dot-length-equals-two for possible solution
```
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