performanceObserverEntryList.getEntriesByType(type) function in Node.js

The performanceObserverEntryList.getEntriesByType(type) function in Node.js is used to get the PerformanceObserverEntryList where the specified PerformanceEntry is to be observed. It is helpful for matters of logging and profiling WebApps and evaluate the WebApps' performance about tasks, such as loading resources, navigating to certain areas, or measuring specific metrics.

Overview:

Function: getEntriesByType(type)

Type Parameter: A string that specifies the type of performance entry to be returned. There are many types but it is the most common types are 'mark', 'measure', 'resource', and 'navigation'.

Returns: A list of performance entries that correspond to the indicated type.

How does it work?

The PerformanceObserver API is a JavaScript API utilized for observing performance occurrences because they take place in real time. If the observer is triggered, it has access to PerformanceObserverEntryList containing all the performance entries. If we invoke the getEntriesByType(type) function on this list, we exclude entries by type and then study the particular performance statistics.

Features of performanceObserverEntryList.getEntriesByType(type):

Several features are as follows:

1. Real-Time Performance Data Collection:

It stores performance data in real-time, which means that the information about the output of a particular machine can be analyzed as soon as it is produced. It is very important for applications that require fast response time concerning some form of degradation.

2. Support for Buffered Entries:

The observer can be set to use buffered entries and this simply refers to the performance data gathered at a time before the observer was setup. It means that no performance data is omitted, which offers a comprehensive view of the application performance.

3. Detailed Insights into Resource Loading:

It offers detailed information about each performance entry, for instance, start time, duration, and the actual names of the resources used. It is beneficial for such tasks as effective resource loading time and for finding the assets that are loaded slowly, thus affecting the overall application's speed.

4. Customizable Performance Monitoring:

When it is used in conjunction with the custom marks and measures, getEntriesByType provides the flexibility to develop unique performance metrics that address unique application requirements. This makes it possible to monitor any important part of the code whenever it is necessary.

5. Integration with Performance APIs:

It is very compatible with other performance APIs when used in Node.js, such as Performance.Mark() and Performance.measure(), to develop scenarios that generate performance entries that can then be identified and monitored.

Example:

Let us take a Program to illustrate the performanceObserverEntryList.getEntriesByType(type) function in Node.js:

Output:

Use Cases of performanceObserverEntryList.getEntriesByType(type):

Several uses cases of this function are as follows:

Resource Load Analysis:

• By observing the 'resource' type entries, we can see how long different resources load on our web application, such as images, scripts, and CSS files. It helps in enhancing the rate of resource loading.

Navigation Timing:

• It is possible to track page navigation performance metrics, such as the time required to load a page by observing the 'navigation' entries. It is especially applicable for performance auditing and to determine the areas of improvement.

Monitoring Web Vitals:

• If the entries are connected to web vitals, which are FCP and LCP, developers can get an understanding of how their applications perform in terms of real-life usage.

Conclusion:

In conclusion, the performanceObserverEntryList.getEntriesByType(type) function in Node.js is one of the main functions of Node.js that can be used for performance monitoring. Information related to the performance of the analyzed applications can be extremely helpful to their developers, which allows for selective retrieval of performance entries of specific types, which can help to identify the most critical areas requiring optimization.