console methods
- Node.js course
- Intermediate
- Lesson 90/116
- 5 min
Learn console.log, console.error and console.table.
console methods
The console object has many methods beyond console.log. console.error writes to the standard error stream (stderr); console.warn is for warnings; console.info for informational messages.
console.table(data) prints an array or object in tabular form; with column headers it is easier to read. console.time("label") and console.timeEnd("label") measure elapsed time in milliseconds; useful for performance comparisons. console.group and console.groupEnd organize messages into indented groups. Choosing the right method makes output more readable; if errors go to stderr, log systems can capture them separately.
Measuring with console.time
To measure how long an operation takes, use console.time and console.timeEnd. Both take the same label; when the labels match, the elapsed time is printed.
Example: console.time("loop"); for (let i = 0; i < 1000; i++) {} console.timeEnd("loop");. Output: loop: 0.123ms. The time is in milliseconds; small differences are visible. Multiple time calls with the same label each keep a separate counter. This is practical for comparing algorithms or finding a slow loop. We are learning console.time here, not performance.now from a later lesson; this one is accurate enough.
Practice Log a record with console.log
Define const record = { name: "Ayşe", age: 30 };. Start with console.log("Console started"). Print the record with console.log("Record: " + record.name + ", age: " + record.age). End with console.log("Console ended").
Starter code
// Define the record object
// write here
// Print "Console started"
// write here
// Print "Record: ..."
// write here
// Print "Console ended"
// write hereSample solution
const record = { name: "Ayşe", age: 30 };
console.log("Console started");
console.log("Record: " + record.name + ", age: " + record.age);
console.log("Console ended");Expected output
Konsol başladı Kayıt: Ayşe, yaş: 30 Konsol bitti
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Match each method to its purpose
| Term | Meaning |
|---|---|
console.log |
General output |
console.error |
Error stream |
console.table |
Tabular format |
console.time |
Measures time |
2 Where does console.error write?
console.error("Hata")- Only to a file
- Nowhere
- To the standard error stream (stderr) Correct answer
- To standard output (stdout)
Explanation: console.error writes to stderr.
3 Complete the console.table call
console.____(kullanicilar);console.table(kullanicilar);Explanation: console.table prints an array as a table.