Node.js Lifecycle
The Node.js lifecycle consists of several phases, each of which involves different operations and processes. These phases are as follows:
Initialization: This phase involves setting up the environment, including loading required modules and initializing global variables. The process.argv and process.env properties, for example, are set during this phase.
Module Loading: During this phase, the required Node.js modules are loaded into memory, and the exports object of each module is made available for use.
Bootstrapping: This is the phase where the main module of the Node.js application is executed. During this phase, the require() function is called to load the necessary dependencies, and the application's logic is executed.
Event Loop: The event loop is the core of Node.js, where it listens for events, processes them and executes callback functions. This is an infinite loop that listens for events and delegates the handling of those events to the appropriate callbacks.
Message Queue: The message queue holds a list of messages (functions) that are waiting to be executed by the event loop. These messages can be the result of an event trigger or the completion of an asynchronous operation.
Tick: During each tick, the event loop checks the message queue for new messages and processes them. If the message queue is empty, the event loop continues to wait for new events.
Termination: When there are no more messages to be processed and no events to be listened to, Node.js can safely terminate the process.
It's important to note that the lifecycle of a Node.js application can be affected by several factors, including the architecture of the application, the number of dependencies and the frequency of events. Understanding the lifecycle of Node.js is crucial for writing efficient and scalable applications.
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