Serialize js-objects in JS logging functions

Features
1

When I log a JS object through the log methods, the object gets serialized to [object Object]. This is never what you want, really - what you DO want is the serialized version (JSON-style).

That is - instead of:

var err = { error: 'such hard to debug' };
log.error(JSON.stringify(err, null, '  '));

, I could simpy do:

var err = { error: 'wow eazi' };
log.info(err);
1 Like
2

Yes, we are aware of this - should probably be a core function?

I assume you are aware of the util library… It has a simple wrapper function called util.log( err ):
https://github.com/enonic/lib-util/blob/master/src/main/resources/site/lib/enonic/util/util.js

3

Yep I know - but why have a utility for logging when there’s a “native” logging function that does the same? Also, there’s no control over info vs warning vs error etc with the util lib.

4

The logging functions follows the following pattern (using string format - http://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html#syntax):

log.<level>(<msg>, <args..>);

So, to log info you can use the following:

log.info('My message');
log.info('My message with param %s', 4);
log.info('My %s with param %s', 'message', 4);

When trying to log JSON objects you can either do it like this (using 4 spaces as indent):

log.info('My JSON %s', JSON.stringify(json, null, 4));

Or using our buildt-in JSON converter:

log.info('My JSON %s', json);

If you use this as the first parameter (message), then it will just do a toSting()on the parameter.

So, no need for the util in the previous post.

Hope that helps.

5

Will this last example take any javascript object and print it as JSON?

6

How do you use the built-in json converter? I tried the log.info('My JSON %s', json); with a component and what I got was not very human readable:

My JSON {"name":"Post single","path":"main/0/left/0","type":"part","descriptor":"com.enonic.theme.superhero:post-single","config":{}}

It’s kind of a pain to write log.info('My JSON %s', JSON.stringify(json, null, 4));

How about log.json(object, level); The “level” param would be “info”, “warning”, “error” etc.

7

It’s printed out as JSON without indention. It’s a lot of variations here and I do not think one solution fits all. The good thing here is that you can always create your own.

exports.json = function(object, level) {
   if (level === 'info') {
      log.info(JSON.stringify(json, null, 4));
   }
   ....
}
8

Yes, any javascrip object and print it as JSON. Arrays, Objects, functions.