The ‘beforeExit’ is an event of class Process within the process module which is emitted when Node.js empties its event loop and has no additional work to schedule.
Syntax:
Event: 'beforeExit'
Parameters: This event does not accept any argument as the parameter.
Return Value: This event returns nothing but a callback function for further operation.
Example 1:
index.js
// Node.js program to demonstrate the // Process 'beforeExit' Event // Importing process module const process = require( 'process' );
// Event 'beforeExit' process.on( 'beforeExit' , (code) => {
console.log( 'Process beforeExit event with code: ' , code);
}); // Event 'exit' process.on( 'exit' , (code) => {
console.log( 'Process exit event with code: ' , code);
}); // Display the first message console.log( 'This message is displayed first.' );
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Run the index.js file using the following command:
node index.js
Output:
This message is displayed first. Process beforeExit event with code: 0 Process exit event with code: 0
Example 2:
index.js
// Node.js program to demonstrate the // Process 'beforeExit' Event // Importing process module const process = require( 'process' );
// Updating the exit code process.exitCode = 100; // Event 'beforeExit' process.on( 'beforeExit' , (code) => {
console.log( 'Process beforeExit event with code: ' , code);
}); // Display the first message console.log( 'This message is displayed first.' );
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Run the index.js file using the following command:
node index.js
Output:
This message is displayed first. Process beforeExit event with code: 100
Reference: https://nodejs.org/dist/latest-v16.x/docs/api/process.html#process_event_beforeexit