Error Handling and Debugging

Debugging Techniques

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LearnStep 1 of 3

Modern JavaScript Debugging

Learning Objectives

•Utilize advanced console methods like table, group, and time for structured logging
•Implement effective breakpoint strategies using the debugger statement and browser DevTools
•Debug asynchronous code by leveraging the Async call stack in modern browsers
•Identify performance bottlenecks using basic profiling techniques to optimize execution

Lesson Outline

LearnStep 1/3

Modern JavaScript Debugging

Advanced Console Methods

Beyond console.log, the console API provides powerful tools for visualizing data and measuring performance.

console.table(): Renders an array or object as a table, making it easy to inspect large datasets.
console.group() / console.groupEnd(): Groups related logs together, which can be collapsed in the DevTools.
console.time() / console.timeEnd(): Measures the duration of a specific operation by its label.

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Using Breakpoints

While logging is useful, breakpoints allow you to pause execution and inspect the entire state of the application. You can set them in the Sources tab of DevTools or use the debugger keyword in your code.

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Async Debugging

Debugging async/await or Promises can be tricky because the stack trace might get lost. Modern browsers provide an Async Call Stack feature that allows you to see the chain of events that led to an asynchronous callback.

Profiling and Performance

The Performance tab in browser DevTools allows you to record a 'profile' of your application. You can see which functions are taking the most time and identify 'Long Tasks' that block the main thread, causing UI lag.