Summary - Debugging

Combine inspect, console and util.inspect to write a debug session.

Summary - Debugging

In this group you learned Node.js's debugging tools: the node inspect terminal debugger, the Chrome DevTools visual interface, console methods, object inspection with util.inspect, and source map mapping to the original source. Now we will combine them in a debugging helper.

Structure: format objects with util.inspect, give general output with console.log, write errors separately with console.error. This is a small example of what a logging helper looks like in a real project. Choosing the right tool during debugging saves time: console.log for quick inspection, DevTools for visual inspection, node inspect for stepping line by line.

Exercise Write a debugging helper

Import with const util = require("node:util");. Define const record = { name: "Ayşe", age: 30, grades: [85, 90, 78] };. Define function debugLog(title, data) { console.log(title + ": " + util.inspect(data, { depth: 2, colors: false })); }. Call with debugLog("Record", record). Add console.log("Debugging done").

Show example solution

const util = require("node:util");
const record = { name: "Ayşe", age: 30, grades: [85, 90, 78] };
function debugLog(title, data) {
  console.log(title + ": " + util.inspect(data, { depth: 2, colors: false }));
}
debugLog("Record", record);
console.log("Debugging done");

Test yourself

Which tool is best for inspecting a complex object?
```
util.inspect(obj, { depth: 3 })
```
- Only console.log
- Only process.exit
- Formatting with util.inspect and passing it to console.log
- throw new Error
Show answer

Formatting with util.inspect and passing it to console.log — util.inspect formats the object readably.
Match each tool to its purpose

node inspect

Terminal debugger
DevTools

Visual interface
console.error

Error stream
util.inspect

Object formatting

Complete the inspect call

console.log(util.____(record, { depth: 2 }));

Show answer

console.log(util.inspect(record, { depth: 2 }));

Next lesson: The Date object

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