example-smart-wallet/packages/nextjs/utils/truncate-address.ts

// Captures 0x + 4 characters, then the last 5 characters.
const truncateRegex = /^(0x[a-zA-Z0-9]{4})[a-zA-Z0-9]+([a-zA-Z0-9]{5})$/;

const truncateAddress = (address: string) => {
  const match = address.match(truncateRegex);
  if (!match) return address;
  return `${match[1]}...${match[2]}`;
};

export default truncateAddress;