Return the text unchanged when columns is NaN

[hong4rc]

Issue

When columns is NaN, the input is returned with a truncation character always appended — so the output is longer than the input and nothing is actually truncated. It happens for any input, even an empty string:

input	current	expected
''	'…'	''
'hi'	'hi…'	'hi'
'unicorns'	'unicorns…'	'unicorns'

Easy repro

import cliTruncate from 'cli-truncate';

cliTruncate('unicorns', NaN);
//=> 'unicorns…'   ❌ not truncated, stray "…" appended

How NaN shows up in practice

The common idiom of reserving a margin off the terminal width:

cliTruncate(text, process.stdout.columns - 2);

When stdout is not a TTY (piped to a file, redirected, or CI), process.stdout.columns is undefined, so undefined - 2 is NaN:

$ node demo.js > out.txt   # stdout is not a TTY
$ cat out.txt
this is a long status line…   ← stray "…", not truncated

Fix

A NaN budget means the target width is unknown, so return the text untruncated instead of appending a truncation character. Other non-finite inputs are unchanged: Infinity already returned the text, negatives already returned ''.

Added a NaN columns test (plain + ANSI-styled input).

[sindresorhus]

This should throw instead. columns is expected to be an actual width, and NaN is not a meaningful terminal column count. The process.stdout.columns - 2 case should be handled by the caller with an explicit fallback, rather than making cli-truncate silently opt out of truncation.