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The dnsPromises.resolve4() method uses the DNS protocol to resolve IPv4 addresses (A records) for the hostname. A promise is resolved with an array of IP addresses when True.The difference between the dnsPromises and dns module is that dnsPromises provides an alternative way to asynchronous DNS methods that return Promise objects instead of callbacks.Syntaxdns.resolve4(hostname, [options])Parametershostname – This parameter takes input for hostname to be resolved.options – It can have the following options −ttl – This defines the Time-To-Live (TTL) for each record. Callback receives an array of addresses like this – { address: ‘1.2.3.4’, ttl:60 }Example 1Create a file "resolve4.js" and ... Read More
The dns.resolveNaptr() method uses the DNS protocol to resolve regular expression based words (NAPTR records) for the hostname. The addresses argument passed to the callback function will contain an array of objects with the following properties −flagsserviceregexpreplacementorderpreferenceSyntaxdns.resolveNaptr(hostname, callback)Parametershostname – This parameter takes input for the hostname to be resolved.callback – This function will catch errors, if any.Records – Returns NAPTR records for the hostname.Example 1Create a file "resolveNaptr.js" and copy the following code snippet. After creating the file, use the command "node resolveNaptr.js" to run this code.// dns.resolveNaptr() Demo Example // Importing the dns module const dns = require('dns'); ... Read More
The dns.lookupService() method resolves the given address and port into a hostname and service. This method uses the operating system’s underlying getnameinfo implementation.A TypeError will be thrown if the address is not a valid IP address. The difference between the dnsPromises and dns module is that dnsPromises provides an alternative way to asynchronous DNS methods that return Promise objects instead of callbacks.SyntaxdnsPromises.lookupService(address, port)Parametersaddress – This parameter takes input for the IP address that needs to be resolved.port – This parameter takes input for the port number that is attached with the IP address.Example 1Create a file with the name "lookupService.js" ... Read More
An ‘exit’ event is emitted when the process is going to exit due to the following reasons −Process.exit() method is called explicitly.The node event loop no longer have any task to perform.SyntaxEvent: 'exit'Example 1Create a file "exit.js" and copy the following code snippet. After creating the file, use the command "node exit.js" to run this code.// Process 'Exit' event Demo Example console.log("Process Starts") // Binding this event to the handler process.on('exit', () => { console.log("process.exit() method is called") }) console.log("Process Ends") // Exiting the process process.exit()OutputProcess Starts Process Ends process.exit() method is calledExample 2Let’s take a ... Read More
The process.report.filename property is used to get or set the filename where the report will be written. If this value is set as an empty string, the output filename will be made as per the timestamp, PID and sequence number. Its default value is an empty string.Syntaxprocess.report.filenameExample 1Create a file with the name "filename.js" and copy the following code snippet. After creating the file, use the command "node filename.js" to run this code.// process.report.directory Property Demo Example // Importing the process module const process = require('process'); // Passing the filename process.report.filename = "tutorialspoint" // Printing the result ... Read More
SolutionNFA for the above language will be −Conversion from NFA to DFA −ε − closure(0) = {0, 1, 4} = AFor State AFor input symbol aFor input symbol bFor input symbol c∴ Ta = {2}∴ Tb = {5}Tc = ∅∴ ε − closure (Ta) = ε − closure (2)= {2} = B∴ ε − closure (Tb) = ε ... Read More
The dns.getServers() method returns an array of IP address strings. The address will be formatted as per the RFC 5952 standard, that are configured for DNS resolution. The string will also include the port section if a custom port is used.Syntaxdns.getServers()ParametersSince it returns the list of the servers, it does not need any parameters.Example 1Create a file "getServers.js" and copy the following code snippet. After creating the file, use the command "node getServers.js" to run this code.// dns.getServers() Node js Example // Importing the dns module const dns = require('dns'); // Reading the IP related info // for ... Read More
diffieHellman.getPrime() returns the Diffie-Hellman generated prime with the specified encoding. It returns a string in case the encoding is passed, else a buffer will be returned.SyntaxdiffieHellman.getPrime([encoding])ParametersIt takes only one parameterencoding – This parameter specifies the encoding of the return value.Example 1Create a file with the name "prime.js" and copy the following code snippet. After creating the file, use the command "node prime.js" to run this code.// diffieHellman.getPrime() Demo Example // Importing cryptoDiffieHellman from the crypto module const { createDiffieHellman } = require('crypto'); // Initializing the diffieHellman const dh = createDiffieHellman(512); // Generating prime from diffieHellman let dhPrime ... Read More
The dnsPromises.resolveTxt() method uses the DNS protocol to resolve the text search (TXT records) for the hostname. The promise is resolved with a twodimensional array of the text records available for the hostname on success.SyntaxdnsPromises.resolveTxt(hostname)ParametersIt takes only one parameterhostname – This parameter takes input for the hostname to be resolved.Example 1Create a file with the name "resolveTxt.js" and copy the following code snippet. After creating the file, use the command "node resolveTxt.js" to run this code.// dns.resolveTxt() Demo Example // Importing the dns module const dns = require('dns'); const dnsPromises = dns.promises; // Passing IP to find the ... Read More
The dnsPromises.lookup() method resolves the hostname (e.g., tutorialspoint.com) into the first found A IPv4) or AAAA (IPv6) record. The properties available under the options are optional.dns.lookup() does not have anything to do with the DNS protocol. The implementation uses an OS facility that can associate names with addresses and vice versa.The difference between the dnsPromises and dns module is that dns.promises provides an alternative way to asynchronous DNS methods that return Promise objects instead of callbacks.SyntaxdnsPromises.lookup(hostname, [options])Parametershostname – This is the website hostname for which you want to look up the DNS values.options – It can have the following optionsfamily ... Read More