Node.js console.log vs console.info

Question

What is the benefit of using console.log vs console.info? Or any of the other console commands for that matter?

console.info("info");
console.error("error");
console.warn("warn");

vs

console.log("log");

I thought it might change the color of the output or concatenate some sort of label, but they seem to all do the same thing. And according to the documentation here:

https://nodejs.org/api/console.html#console_console_info_data

they seem to all do the same as console.log

Possible duplicate of: https://stackoverflow.com/questions/14437428/what-is-the-difference-between-util-error-and-console-error-in-node-js — Craig Wayne, Dec 14 '17 at 00:19
Some tips: You can use colors to have a better view of: console.log('%c Sample Text', 'color:green;'); Or add some VAR in the text using: console.log(\`Sample ${variable}\`, 'color:green;'); — Gilberto B. Terra Jr., Jan 29 '19 at 11:31
I definitely wrap all my logging functionality in an in house adapter or some logging library but I think the difference between `log` and `info` is an interesting idealogical question. I personally think `debug` is (naturally) for debugging, `log` is for extra context that may be verbose (contrary to Chrome's devtools logging levels filter) and `info` is for logging important context changes like a routing change in a SPA or sign-in/out changes. Honestly still an up-to-you / YMMV situation imo ‾\\_(ツ)_/‾ — Keego, Sep 16 '22 at 03:16

score 121 · Accepted Answer · edited Mar 16 '23 at 20:07

121

According to the documentation that you linked to, console.error and console.warn output to stderr. The others output to stdout.

If you are doing piping or redirection from node.js the difference is important.

There is a lot of JavaScript written to run in both the browser and Node.js. Having node implement the full console allows for greater code cross-compatibility.

In most browsers, not only do these log in different colors, but you can also filter to see specific messages.

console.debug("debug"); // Likely hidden by default
console.info("info");
console.error("error");
console.warn("warn");
console.log("log");

edited Mar 16 '23 at 20:07

zcoop98

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answered Aug 27 '14 at 16:53

Jeremy J Starcher

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Thank you! It was the browser where it shows up differently. I was looking in terminal for the color changes. – seantomburke Aug 27 '14 at 16:57
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In `node` (`8.11.4`) and Chrome 67, there's also `console.debug` (and quite likely earlier versions as well). `debug` ranks below `log`. – Marcus Junius Brutus Oct 04 '18 at 20:02

score 79 · Answer 2 · edited Jul 02 '22 at 10:16

79

While console.log and console.info might seem the same, with only mere coloring differences (in most browsers), you can take advantage of having these differently named functions.

For example, you can configure a linter like eslint to produce a warning message whenever console.log is used but no warnings for console.info. Now you can use console.log for temporary development/debug logging and console.info for information that end users might need. The linter warnings will remind or even force you to removed the temporary console.log calls before commits code or publishing release builds.

edited Jul 02 '22 at 10:16

Inigo

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answered Aug 19 '17 at 00:09

Figidon

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I dont know why I found this answer more appropriate then all others, nice one @Figidon . – Shreyan Mehta Jun 13 '18 at 07:39
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I concurr. Great solution to use with eslint for dev and production mode. You shall not pass console.log! (staff and sword in hand) – Tomas Vancoillie Jan 10 '20 at 12:17
Also monitoring tools, such as DataDog, automatically place logs produced by `console.info`, `console.error`, and `console.warn` into the categories "Info", "Error", and "Warn" respectively which allows for further log filtering. – uzluisf Mar 03 '23 at 14:51

Max · Answer 3 · 2020-07-28T13:12:11.237

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console.log() is shorter than console.info()

They're the same thing, and that's the only advantage.

edited Jul 28 '20 at 13:12

answered Aug 28 '14 at 00:59

Max

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I downvote because "that's the only advantage" is simply not true and quite shortsighted. The methods may well have exactly the same implementation, but they have different **meaning**. console lets you implement log level filtering trivially for example. – rixo Jan 29 '16 at 14:36
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console.log = stdout, whilst console.error = stderr – Craig Wayne Dec 14 '17 at 00:18
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https://developer.mozilla.org/en-US/docs/Web/API/Console/info -- "In Firefox and Chrome, a small "i" icon is displayed next to these items in the Web Console's log" -- https://image.ibb.co/gYrZHe/infolog.png – ed' Aug 23 '18 at 12:41
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@EdwardSammutAlessi I'm using Chrome and wasn't able to recreate and get the i icon to appear – chevybow Mar 08 '19 at 18:43
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One datapoint: Firefox 78: prints ⓘ (i in circle) before log.info output. Chrome 84: doesn't. – Tom Hundt Jul 28 '20 at 17:20
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One other advantage: I almost always use console.log for debugging. Though sometimes I actually want to log things (e.g. in a node CLI app). Before I commit my code I'll often do an "ack console.log" to see if I left any console.logs in my code. But this will catch my actual logs too. So I use console.info to indicate "I want this to stay here, it isn't for debugging." – Cully Feb 19 '21 at 02:50
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It was funny answer. – Alok Deshwal Aug 21 '21 at 08:35
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@Cully why not use console.debug for debugging ? – TheToto Nov 26 '21 at 14:58
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@ThomasLupin It's two characters longer ;) – Cully Nov 27 '21 at 04:49
Turns out you can just put `this.l = (...args) => console.log(...args)` in global scope and its even shorter _AND_ browser + Node compliant. `l('nyancatftw')` boom done – Keego Sep 16 '22 at 03:07

score 31 · Answer 4 · edited Jun 20 '20 at 09:12

31

According to the docs it's pretty clear.

console.info([data], [...])# Same as console.log.

console.error([data], [...])# Same as console.log but prints to stderr.

console.warn([data], [...])# Same as console.error.

This means there is no benefit or downside. info == log, and warn == error. Unless you want to print to stderr, info and or log will work.

edited Jun 20 '20 at 09:12

Community

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answered Aug 27 '14 at 16:51

Sterling Archer

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I mean, log vs info may be ambiguous but I'm pretty sure the concept of warnings vs errors is a thing in software development. Chrome dev console will log a stack trace for both warn and error but they're colored differently. Similar with running tests in Jest with Node – Keego Sep 16 '22 at 03:10

score 28 · Answer 5 · answered Nov 11 '16 at 19:23

Visually, No difference actually among console.log , console.info , console.warn , as well as console.error regarding the server side(terminal).

However, there are lightweight modules that add blue, orange and red colors for console.info , console.warn , as well as console.error respectively . By that, console API behaves like client-side.

 npm i console-info console-warn console-error --save-dev;

score 12 · Answer 6 · answered Sep 15 '14 at 02:10

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One more detail in addition to the accepted answer: In Chrome and FireFox, console.info log lines are prefixed with a little i icon while console.log lines are not. warn and error lines are prefixed with a little triangle and x, respectively.

answered Sep 15 '14 at 02:10

Bill Hoag

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As observed elsewhere: Firefox 78: prints ⓘ (i in circle) before log.info output. Chrome 84: doesn't – Tom Hundt Jul 28 '20 at 17:23
Is it possible that the behavior for console.info was changed? I don't see any "i icon" in Chrome... – gignu May 29 '22 at 20:41

score 9 · Answer 7 · answered Sep 12 '18 at 10:55

stdin A readable stream for reading input from the user.

stdout A writable stream, either synchronously or asynchronously.

stderr A blocking synchronous writable stream intended for error messages.

The stdout or non-blocking functions are: console.log, console.info, util.puts, util.print and Stderr.

The blocking functons are: console.warn, console.error, util.debug and process.stdin (a readable stream for getting user input).

score 5 · Answer 8 · answered Jun 01 '20 at 04:20

It has been established that log and info are basically the same thing, but I'm not sure that completely answers the question:

What is the benefit of using console.log vs console.info?

One benefit, apart from what has already been mentioned, is you can use each for a different purpose. For example, you might use console.log just for quick debugging and spitting things out to the console, while you might use console.info for permanent messages you want to output to the console in your code, such as information on the current app status. Then when you have a situation where a random object is printed in your console and you realize you've left a log statement in there somewhere by accident, you can do a global search for 'console.log' and delete every instance and have confidence you didn't delete anything important that you meant to leave in there.

score 4 · Answer 9 · answered Oct 27 '20 at 02:14

I have seen where console.log is for temporarily logging of state information for debugging.

console.info is a more permanent thing - such as saying what port something is running on, and something you wouldn't cut out after you are done debugging.

This makes it easy to clean up your code for committing it. You can even have your linter have a rule to prevent console.log from being committed.

score 4 · Answer 10 · answered Sep 15 '21 at 22:54

There is a difference for React devs. It comes from an issue in the react devtool extension and at least affects Create-React-App users, not sure if it's all web pack.

Issue is mentioned here: react devtools console.log() from react_devtools_backend.js:4049

but the jist is: console.log will always report its source as

react_devtools_backend.js:4049

wheres console.info will have the actual filename and line number you're logging from.

Useful, even 6 years later, to know this. – mckenzm Nov 07 '21 at 21:56 — mckenzm, Nov 07 '21 at 21:56

score 2 · Answer 11 · answered Jul 28 '20 at 17:34

The different logging levels let you manage the noise level in your console: In both the Firefox (I'm using 78 right now) and Chrome (84) devtools, the js console lets you choose what "debug level" of output you want to see. FF lets you toggle the visibility of console.error, .warn, .log, .info, and .debug messages by clicking individual buttons for each (that show you how many were suppressed, when "off"), whereas Chrome has a dropdown with checkmarks next to the items (.info and .log are controlled by the "Info" one, and .debug by "Verbose"). The Chrome dropdown label ("All levels" or whatever you set) turns red if output was suppressed.

score 0 · Answer 12 · answered Aug 22 '23 at 03:45

A hopefully concise explanation of when to use each of these console methods in JavaScript:

console.info("info");
- Use when providing informative messages or general information.
- Code:
```
console.info("Connection established.");
```
console.error("error");
- Use for reporting errors or exceptions.
- Code:
```
console.error("File not found.");
```
console.warn("warn");
- Use for warnings that need attention but aren't necessarily errors.
- Code:
```
console.warn("Deprecated function used.");
```
console.log("log");
- General-purpose logging, mainly for debugging or displaying general messages.
- Code:
```
console.log("Variable value:", variable);
```

Node.js console.log vs console.info

12 Answers12

A hopefully concise explanation of when to use each of these console methods in JavaScript:

Linked