Answer:- The control flow does the following job: • Control the order of execution • Collect data • Limit concurrency • Call the next step in a program

Answer:- No, it is not possible to access DOM in Node.

Answer:- • I/O operations • Heavy computation • Anything requiring blocking

Answer:- REPL stands for Read Eval Print Loop. It specifies a computer environment like a window console or Unix/Linux shell where you can enter a command, and the computer responds with an output. It is very useful in writing and debugging the codes. REPL environment incorporates Node.js.

Answer:- Following are the terms used in REPL with their defined tasks: • Read: It reads users input; parse the input into JavaScript data-structure and stores in memory. • Eval: It takes and evaluates the data structure. • Print: It is used to print the result. • Loop: It loops the above command until user press ctrl-c twice to terminate.

Answer:- Yes. You can evaluate simple expressions using Node REPL.

Answer:- Yes, Node.js Crypto module supports cryptography. It provides cryptographic functionality that includes a set of wrappers for open SSLs hash HMAC, cipher, decipher, sign and verify functions.

Answer:- npm stands for Node Package Manager. Following are the two main functionalities of npm: • Online repositories for node.js packages/modules which are searchable on search.nodejs.org • Command line utility to install packages, do version management and dependency management of Node.js packages.

Answer:- Following is a list of tools that can be used in developing code in teams, to enforce a given style guide and to catch common errors using static analysis. • JSLint • JSHint • ESLint • JSCS

Answer:- Operational errors are not bugs, but create problems with the system like request timeout or hardware failure. On the other hand, programmer errors are actual bugs.

Answer:- • Global installation of dependencies is stored in /npm directory. While local installation of dependencies stores in the local mode. Here local mode refers to the package installation in node_modules directory lying in the folder where Node application is present. • Globally deployed packages cannot be imported using require() in Node application directly. On the other hand, locally deployed packages are accessible via require(). • To install a Node project globally -g flag is used. C:Nodejs_WorkSpace>npm install express ?g • To install a Node project locally, the syntax is: C:Nodejs_WorkSpace>npm install express

Answer:- The Node.js Assert is a way to write tests. It provides no feedback when running your test unless one fails. The assert module provides a simple set of assertion tests that can be used to test invariants. The module is intended for internal use by Node.js, but can be used in application code via require (assert).

Answer:- The Streams are the objects that facilitate you to read data from a source and write data to a destination. There are four types of streams in Node.js: • Readable: This stream is used for reading operations. • Writable: This stream is used for write operations. • Duplex: This stream can be used for both reading and write operations. • Transform: It is a type of duplex stream where the output computes according to input.

Answer:- In Node.js, event-driven programming means as soon as Node starts its server, it initiates its variables, declares functions and then waits for an event to occur. It is one of the reasons why Node.js is pretty fast compared to other similar technologies.