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The dns.lookupService() method resolves a 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.Syntaxdns.lookupService(address, port, callback)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.callback - It will catch errors, if any.Example 1Create a file with the name "lookupService.js" and copy the following code. After creating the file, use the command "node lookupService.js" to run this ... Read More
In this article, we'll use C++ to calculate the number of weight W paths in a K-ary tree in this article. We've given a K-ary tree, which is a tree in which each node has K children and each edge has a weight assigned to it, with weights descending from 1 to K from one node to all of its children.We need to count the cumulative number of paths beginning from the root that have a weight of W and at least one edge with a weight of M. So, here's example −Input : W = 4, K = 3, ... Read More
The diffieHellman.setPrivateKey() sets the Diffie-Hellman generated private key. The private key will be a string if an encoding argument is provided. If no encoding is provided, the private key will be of type buffer.SyntaxdiffieHellman.setPrivateKey( privateKey, [encoding] )Parametersencoding - This parameter specifies the encoding of the private Key.Example 1Create a file with the name "privateKey.js" and copy the following code. After creating the file, use the command "node privateKey.js" to run this code as shown in the example below// diffieHellman.setPrivateKey() Demo Example // Importing the crypto module const crypto = require('crypto') // Generating the key pairs(public & private) crypto.generateKeyPair('rsa', ... Read More
A 'warning' event is emitted whenever a Node.js event emits a process warning. The process warning is similar to an error that describes the exceptional conditions that are being brought to the user's attention.Node.js can emit warnings whenever it encounters any bad coding practices that could lead to poor performance or bugs.SyntaxEvent : 'warning'Example 1Create a file with the name "warning.js" and copy the following code. After creating the file, use the command "node warning.js" to run this code, as shown in the example below// Event: warning Demo Example // Importing the process module const process = require('process'); ... Read More
The Timeout object is internally created and is returned from the setTimeout() and setInterval() methods. You can use this object and pass it to either clearTimeout() or clearInterval() if you want to cancel the scheduled actions.Following are the timeout class ref objects that can be used to control the default behaviour −1. timeout.ref()This method is called if the timeout object's event loop does not exist. The actual use of this method is only after the timeout.unref() is called, and you need to reference the timeout object again.Syntaxtimeout.ref()2. timeout.unref()This method will tell the timeout object that the Node.js event loop does not ... Read More
Redis also supports the monitor command that lets the user to see all the commands received by the Redis server across all the client connections. These connections include commands from everywhere, including other client libraries and computers as well.The monitor event will monitor all the commands which are executed on the Redis server where monitor is enabled. The callback from the monitor receives the timestamp from the Redis server, an array of commands along with the raw monitoring string.Syntaxclient.monitor( function(callback) )Example 1Create a file with the name "monitor.js" and copy the following code. After creating the file, use the command "node ... Read More
WaveCluster is a multiresolution clustering algorithm that first summarizes the records by imposing a multidimensional grid architecture onto the data space. It can use a wavelet transformation to change the original feature space, finding dense domains in the transformed space.In this method, each grid cell summarizes the data of a group of points that map into the cell. This summary data generally fit into the main memory for use by the multiresolution wavelet transform and the subsequent cluster analysis.A wavelet transform is a signal processing approach that decomposes a signal into multiple frequency subbands. The wavelet model can be used ... Read More
The grid-based clustering methods use a multi-resolution grid data structure. It quantizes the object areas into a finite number of cells that form a grid structure on which all of the operations for clustering are implemented. The benefit of the method is its quick processing time, which is generally independent of the number of data objects, still dependent on only the multiple cells in each dimension in the quantized space.An instance of the grid-based approach involves STING, which explores statistical data stored in the grid cells, WaveCluster, which clusters objects using a wavelet transform approach, and CLIQUE, which defines a ... Read More
The stringDecoder.end() method will return any remaining input that is left in the internal buffer as a string. Bytes that are left incomplete and represent UTF-8 and UTF-16 characters are replaced with the substitution characters appropriate for character encoding.StringDecoder.write() method is called before returning the remaining input if any buffer argument is provided. The stringDecoder can be reused for taking new inputs once the end() method is called.SyntaxstringDecoder.end( [buffer] )Parametersbuffer - This parameter takes input for the bytes to decode. It can take buffer, TypedArray or DataView as the input parameters.Example 1Create a file with the name "end.js" and copy ... Read More
The retry_strategy is a function that receives objects as parameters including the retry attempt, total_retry_time that indicates the time passed after it was connected the last time, the error due to which the connection was lost, and the number of times_connected in total.If a number is returned from this function, the next retry will take place after that time only in milliseconds and if you send a non-number, no further retry will take place.Syntaxretry_strategy: funciton(options)Example 1Create a file with the name "retryStrategy.js" and copy the following code. After creating the file, use the command "node retryStrategy.js" to run this code ... Read More