Truncate a string at full words

Cut at the last space that fits, then add a suffix.

JavaScript Version 1.0.0 · MIT · .md

function truncateWords({ text, max, suffix }) { if (text.length <= max) return text; const cut = text.slice(0, max - suffix.length); const space = cut.lastIndexOf(' '); return `${space > 0 ? cut.slice(0, space) : cut}${suffix}`; }

Input & expected output

{
  "text": "Your order 8812 is out for delivery",
  "max": 20,
  "suffix": "…"
}

"Your order 8812 is…"

The edge case

{
  "text": "Supercalifragilistic",
  "max": 10,
  "suffix": "…"
}

"Supercali…"

Know the limits

• The original truncated strings exactly max long and returned only the suffix when the first word was too long; both are fixed.
• Handy for preview text and notification titles; length is in UTF-16 code units.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Capitalize a string — Uppercase the first Unicode code point and preserve the remaining text.
• Reverse a string — Reverse Unicode code points without splitting surrogate pairs.
• Check a palindrome — Compare a string with its code-point reversal.