Profiling refers to analyzing and measuring an application's performance characteristics.

Profiling helps identify performance bottlenecks in a Node.js app, such as CPU-intensive tasks like cryptographic operations, image processing, or complex calculations.

This post covers running a profiler for various Node.js apps in Chrome DevTools.

Prerequisites

• Google Chrome installed

• Node.js app bootstrapped

Setup

• Run node --inspect app.js to start the debugger.

• Open chrome://inspect, click Open dedicated DevTools for Node and then navigate to the Performance tab. Start recording.

• Run load testing via autocannon package using the following command format npx autocannon <COMMAND>.

• Stop recording in Chrome DevTools.

Profiling

On Perfomance tab in Chrome DevTools open Bottom-Up subtab to identify which functions consume the most time.

Look for potential performance bottlenecks, such as synchronous functions for hashing (pbkdf2Sync) or file system operations (readFileSync).

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Debugging with a debugger and breakpoints is recommended rather than using console logs. Chrome provides a built-in debugger for JavaScript-based apps.

This post covers configuring and running a debugger for various Node.js apps in Chrome DevTools.

Prerequisites

• Google Chrome installed

• Node.js app bootstrapped

Setup

Open chrome://inspect, click Open dedicated DevTools for Node and open the Connection tab. You should see a list of network endpoints for debugging.

Run node --inspect-brk app.js to start the debugger, it will log the debugger network. Choose the network in Chrome to open the debugger in Chrome DevTools.

Debugging basics

The variables tab shows local and global variables during debugging.

The step over next function call option goes to the following statement in the codebase, while the step into next function call option goes deeper into the current statement.

Add logs in the debug console via logpoints by selecting the specific part of the codebase so it logs when the selected codebase executes.

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