String.prototype.normalize

const a = '\u00F1';           // 'ñ' (single NFC codepoint)
const b = 'n\u0303';          // 'ñ' (n + combining tilde, NFD)
console.log(a === b);          // false — different code points
console.log(a.normalize() === b.normalize()); // true — both NFC after normalize()

The two literals render identically but are different code point sequences. normalize() (defaulting to NFC) reconciles them.

console.log('ñ'.normalize('NFD') === 'ñ'.normalize('NFD'));

Prints true

console.log('ñ'.normalize('NFD').length);

Prints 2

console.log('①'.normalize('NFKC'));

Prints '1'