Text Reverser

String reversal is one of the most common operations in programming interviews and text processing. This tool offers two modes: character reversal (flipping 'hello' to 'olleh') and word order reversal (flipping 'one two three' to 'three two one').

Three concrete scenarios: a developer practicing the 'reverse a string' coding interview classic and wanting to check their answer against a reference implementation that handles Unicode correctly (naïve code using split('').reverse().join('') mangles emoji); a classroom teacher generating a backwards-spelling puzzle for a vocabulary exercise; an editor reformatting a spreadsheet of 'Surname, Firstname' entries back into 'Firstname Surname' order by reversing word order and trimming the comma. Each case demands different behavior, which is why both modes are available as separate buttons rather than hidden behind a single mode switch.

Under the hood, character reversal uses Array.from(str).reverse().join(''), which iterates grapheme clusters rather than UTF-16 code units. This matters because many emoji are represented as surrogate pairs (one emoji = two code units), and skin-tone modifiers or regional flag sequences compose multiple code points into one visible character. The naïve 'split'' approach breaks these and produces garbled output; Array.from handles them because the JavaScript iterator protocol walks by code point. Word reversal splits on whitespace runs, reverses the resulting array, and joins with single spaces — which normalizes consecutive spaces to one, an intentional side effect that's usually what you want.

Limitations: combining characters (an accent that attaches to the preceding letter) are still a single grapheme per the Unicode standard, but some legacy text uses combining sequences that look the same as precomposed characters — those reverse correctly too because Array.from respects the iterator protocol. Compared to writing a one-liner in Python or pasting into an online reverser that re-uploads to a server, this tool is faster and keeps your text local. All processing runs in your browser — your text never leaves your device.