Node.js dnsPromises.resolve4() Method

The dnsPromises.resolve4() method is an inbuilt application programming interface of the promises of dns module which is used to resolve IPv4 address (‘A’ record) for the specified hostname using DNS protocol.

Syntax:

dnsPromises.resolve4( hostname, options )

Parameters: This method has two parameters as mentioned above and described below:

• hostname: This parameter specifies the string which denotes the hostname to be resolved.
• options: It is in the form of an object.
  • ttl: It is a Boolean parameter that specifies whether the Time-To-Live value (TTL) for each record to be retrieved or not. If set to true, TTL for each record is retrieved (in seconds).

Return Value: This method returns error, records.

Below examples illustrate the use of dnsPromises.resolve4() method in Node.js:

Example 1:

// Node.js program to demonstrate the
// dnsPromises.resolve4() method

// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;

// Calling dnsPromises.resolve4() method
dnsPromises.resolve4('geeksforgeeks.org').then((res) => {
    console.log(res);
});

// Calling dnsPromises.resolve4() method
// asynchronously
(async function() {

    // Records from resolve function
    const records = await dnsPromises.resolve4(
                            'geeksforgeeks.org');
    // Printing  records
    console.log("from async: ");
    console.log(records);
})();

Output:

[ '34.218.62.116' ]
from async:
[ '34.218.62.116' ]

Example 2:

// Node.js program to demonstrate the
// dnsPromises.resolve4() method

// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;

// Setting options for dnsPromises.resolve4() method
const options = {
    ttl:true,
};

// Calling dnsPromises.resolve4() method
// asynchronously
(async function() {

    // Records from resolve4 function
    const records = await dnsPromises.resolve4(
                    'geeksforgeeks.org', options);

    // Printing  records
    console.log("from async: ");
    console.log(records);
})();

Output:

from async:
[ { address: '34.218.62.116', ttl: 30 } ]

Note: The above program will compile and run by using the node index.js command.

Reference: https://nodejs.org/api/dns.html#dns_dnspromises_resolve4_hostname_options