Unescape HTML special characters
Turn & < > " and ' back into characters in one pass.
function unescapeHtml(text) { return text.replace(/&(?:amp|lt|gt|quot|#0*39);/g, entity => ({ '&': '&', '<': '<', '>': '>', '"': '"' })[entity] ?? "'"); }Input & expected output
Input
"<b>Ana & Rui</b>"Expected output
"<b>Ana & Rui</b>"The edge case
Input
"&lt;"Expected output
"<"Know the limits
- The original replaced entities one after another, so "&lt;" became "<". A single pass keeps it as "<".
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.
Source & maintenance
Based on Unescape HTML special characters from the original 1loc collection by Nguyen Huu Phuoc. Copyright (c) 2020 phuoc-ng. MIT licensed.
Single pass, so already-escaped entities are not unescaped twice as in the original sequence of replacements. Original MDX retained as inert source evidence.
Maintained by Oveyon. Source commit: 14b481cf60df. Read the license.
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.