Node.js process.report.reportonFatalError() Property

In this article, we will discuss the process.report.reportonFatalError() property in Node.js with its syntax, parameters, and examples.

What is the process.report.reportonFatalError() property in Node.js?

The process object is a global object that stores information about and controls the current Node.js process. It is always available as a global in Node.js applications, so require() is unnecessary. It can also be accessed directly using require(), as shown below.

If the process is complete, a diagnostic report is generated for fatal errors such as out-of-memory or failed C++ assertions when report.reportOnFatalError is set to true.

The process.report.reportOnFatalError property in Node.js is part of the diagnostic reporting feature, which was introduced to assist developers in diagnosing and debugging issues that cause the Node.js process to crash or hang. This feature is especially useful when the program encounters a fatal mistake, and we want to figure out what went wrong.

Syntax:

It has the following syntax:

Parameters:

This property does not have any parameters.

Return type:

This property returns a boolean.

Key Points of the Process.report.reportOnFatalError:

• Purpose: The reportOnFatalError property determines whether a diagnostic report is generated automatically when a fatal error occurs during the Node.js process.
• Fatal errors: Fatal errors in Node.js include uncaught exceptions, unhandled promise rejections, and other critical issues that cause the process to fail unexpectedly.
• Diagnostic Reports: These reports provide detailed information about the state of the Node.js process at the time the error occurred. It includes the stack trace, heap information, environment variables, and any other relevant data that can be used to diagnose the problem.

Example 1:

Let us take an example to illustrate the Node.js process.report.reportonFatalError() property.

Output:

 
A fatal error occurred: This is a fatal error for testing purposes.   

Explanation:

• Enabling Reports: This (process.report.reportOnFatalError = true;) method enables the automatic generation of diagnostic reports when a fatal error happens.
• Setting Directory and Filename: The process.report.directory and process.report.filename properties define the location where the report will be saved. This is optional, and if not specified, the report will be saved in the current working directory with the default filename.
• Triggering a fatal error: The triggerFatalError function simulates a fatal error scenario by throwing an error.
• Detecting Error: The try-catch block is used to catch errors and log them. The diagnostic report will still be generated because the process encountered a fatal error.

Example 2:

Let us take an example to illustrate the Node.js process.report.reportonFatalError() property.

Output:

 
Unhandled Rejection at: Promise {
  <rejected> Error: This is an unhandled promise rejection for testing purposes.
      at Timeout._onTimeout (/home/cg/root/6676fbbe68ebe/main.js:15:20)
      at listOnTimeout (internal/timers.js:554:17)
      at processTimers (internal/timers.js:497:7)
} reason: Error: This is an unhandled promise rejection for testing purposes.
    at Timeout._onTimeout (/home/cg/root/6676fbbe68ebe/main.js:15:20)
    at listOnTimeout (internal/timers.js:554:17)
    at processTimers (internal/timers.js:497:7)
Process running...   

Explanation:

• Supporting Reports: It triggers the generation of diagnostic reports upon encountering fatal errors through the setting process.report.reportOnFatalError = true. We may wish to delve into these details while customizing the Node.js environment.
• Defining Destination and Name: It is not mandatory to provide values for the process.report.directory and process.report.filename. Failure to do so will result in the report being stored in the current working directory under a default name.
• Potential cause of unhandled rejections: The triggerUnhandledRejection function is a synthetic asynchronous operation ending in an unhandled promise.
• Dealing with Unhandled Rejections: We add the process.on('unhandledRejection',...) listener to capture unhandled rejections as information. However, even if a fatal error terminates the process, a report will be generated.

Conclusion:

In conclusion, the process.report.reportOnFatalError property is a powerful Node.js feature that allows diagnostic reports to be generated automatically when fatal errors occur. This capability is invaluable for developers who want to keep their applications robust and resilient because it makes debugging easier and critical issues resolve faster.