@cityssm/is-private-network-address/index.js

Determines whether or not a network address is a private or internal.

/**
 * Local Network Addresses
 */
export const localNetworkAddresses = new Set([
    'localhost',
    '127.0.0.1',
    '::1',
    '::ffff:127.0.0.1'
]);
/*
 * Private Network Address Ranges
 */
export const privateNetworkAddressRanges = [
    /^(::ffff:)?10(\.\d{1,3}){3}$/,
    /^(::ffff:)?172\.(1[6-9]|2\d|3[01])(\.\d{1,3}){2}$/,
    /^(::ffff:)?192\.168(\.\d{1,3}){2}$/,
    /^f[cd][\da-f]{0,2}(:([\da-f]){0,4}){0,7}$/
];
/**
 * Tests if a given network address is a local network address.
 * @param networkAddress - A network address string.
 * @returns `true` if the network address string represents a local network address.
 */
export function isLocal(networkAddress) {
    return localNetworkAddresses.has(networkAddress.toLowerCase());
}
/**
 * Tests if a given network address is a private network address.
 * @param networkAddress - A network address string.
 * @returns `true` if the network address string represents a private network address.
 */
export function isPrivate(networkAddress) {
    if (isLocal(networkAddress)) {
        return true;
    }
    const networkAddressLowerCase = networkAddress.toLowerCase();
    for (const privateNetworkAddressRange of privateNetworkAddressRanges) {
        if (privateNetworkAddressRange.test(networkAddressLowerCase)) {
            return true;
        }
    }
    return false;
}