This technical feature enables your application to accept, parse, and validate both 5-digit US ZIP codes and 6-digit international postal codes (like China's 015107 ) without failing. 1. User Interface (UI) Behavior : Create a single "Postal / ZIP Code" text field.
Apply these conditional regular expression constraints depending on the detected or selected country: Code Example Regex Pattern 015107 ^[0-9]{6}$ United States 90210 ^[0-9]{5}$ United States (ZIP+4) 90210-4321 10 Characters ^[0-9]{5}-[0-9]{4}$ 3. Database Schema (PostgreSQL Example)
{ "input_code": "015107", "is_valid": true, "country": "China", "country_iso": "CN", "region": "Inner Mongolia", "city": "Bayannur" } Use code with caution. Copied to clipboard js backend API endpoint ? 015107 zip
CREATE TABLE user_addresses ( id SERIAL PRIMARY KEY, street_address VARCHAR(255), city VARCHAR(100), state_province VARCHAR(100), -- Always use VARCHAR for postal codes to keep leading zeros postal_code VARCHAR(12) NOT NULL, country_code CHAR(2) NOT NULL ); Use code with caution. Copied to clipboard 4. API Response Model (JSON)
Store postal codes as strings rather than integers to prevent the system from dropping critical leading zeros (such as the 0 in 015107 ). This technical feature enables your application to accept,
: Use the entered code to instantly suggest the corresponding city and country. 2. Regex Validation Rules
as it contains six digits, whereas US ZIP codes strictly use five digits (or nine digits for ZIP+4). However, 015107 serves as a valid postal code for Bayannur, Inner Mongolia, China . CREATE TABLE user_addresses ( id SERIAL PRIMARY KEY,
To build a software feature around this specific data point, it is best to treat it as a problem.
