2

When I fire up node.js in the terminal and run 4 + 4, it outputs 8 as expected. However, when I run the same code but from a file... I get no output unless I use console.log!?

  • Why do I need console.log to output the result, when vanilla js should just do it basically?
  • I thought console.log was code for the browser... Why is it running in node.js? Yes, I know that node.js is built on the same engine that chrome was built on... But still, they are two different products. Doesn't console.log make more sense on the browser side of things than node.js?

Much appreciated.

Improve this question
4
  • 1
    console.log in javascript is just like the System.out.println in Java. It has got nothing to do with browser. The answer given by Fabiano is right. console.log is a syntax of javascript for logging something on to the terminal. In browsers the terminal is the console. That's all. Commented Nov 8, 2019 at 4:44
  • @KaleshKaladharan Thank you for the comparison, but it still doesn't answer my question which was focused on the differences between running js code via terminal vs file. But, yes... I understand his explanation. It makes sense. Commented Nov 8, 2019 at 4:49
  • 1
    There’s a difference between running Node and running its REPL. Commented Nov 8, 2019 at 4:57
  • @SebastianSimon Aah! Thank you for that important distinction. Commented Nov 8, 2019 at 6:37

2 Answers 2

Reset to default
6

Talking about computers, console is a wide concept used main to refer to a terminal where you have an input and output sources. It is likewise your OS shell terminal. So, in Javascript, the console object kind of represents the terminal where it's running your code. Definitely, it's not intended to be a browser thing.

Anyway, when you are running your Javascript code on a terminal prompt, you are inputing and outputting every command and return. Usually it will read your input and print the return value. When you execute a code, from a file, if you want it to read from the running terminal, or to print on it, you must tell your code to do so. This is because when you run a code and you need to tel it to print on your console (console.log) if you want it to do so. So, you tell it to take the return of the expression and print on the console. When you don't tell it to do so, it will return the evaluated expression but it won't print, so you can't see it.

Hope it is of some help.

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

1

Well the console.log function is used as a basic function to literally ,as the name suggests, to log something to the console . When running in an integrated environment such as node.js , it give you an easy to use single-to-multi line execution ,every output is flushed out to console automatically. On the other hand, typing the same code in a JS file t,we are not giving any particular information to the script that it needs to output the answer

For Example:

App.js 

4+4

If we run it in terminal output will be nothing, but if we use

app_console.js

console.log(4+4)

and run it as

$ node app_console.js

it will result as 4 because we are explicitly telling the engine to output it. Several other languages uses they execution in-line console such as Pyshell for Python

Improve this answer

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.