5

I have a small script made with JXA (JavaScript for Automation) that outputs a result to the shell with console.log.

However, console.log seems to output to stderr and I’d like to output to stdout. I can always 2>&1 when calling the script, but it would be preferable to output directly to stdout from the script.

Is there a way to accomplish that?

  • 1
    Close voters: This question on-topic since scripting is specifically listed as being on-topic on this site. – grg Feb 13 '17 at 9:25
  • How are you writing to console.log surely you are writing to stdout or stderr – user151019 Feb 13 '17 at 10:55
  • @Mark Just console.log('whatever'). Nothing out of the ordinary. – user137369 Feb 13 '17 at 23:06
  • Wgat does the documentation for console.log say? – user151019 Feb 13 '17 at 23:14
  • @Mark I never found any official good documentation on JXA. You can’t really deduce this one, though. I don’t have a problem building scripts, I’m asking for the specific function (or option) that’ll do what I need. – user137369 Feb 14 '17 at 17:43
3

Found the solution: don’t use console.log or anything else. Instead of

console.log('something');

Simply

'something';

It will be output to stdout.

  • Only returns last statement – basil Nov 11 '18 at 7:21
  • @basil As would be expected. – user137369 Nov 12 '18 at 12:38
  • But what character encoding will be used? – hendrik Jun 27 at 9:27
1

It may not be the prettiest solution ever, but I think your best bet is to use the Objective-C scripting bridge. The alternative would be to deal directly with the command line and printf, which would probably be even messier.

Using the scripting bridge, you can re-assign console.log to a custom function that writes to stdout using NSFileHandle.fileHandleWithStandardOutput. If you put this definition at the top of your program, you can then use this revised console.log.

console.log = function() {
    ObjC.import('Foundation');
    for (argument of arguments) {
        $.NSFileHandle.fileHandleWithStandardOutput.writeData($.NSString.alloc.initWithString(String(argument) + "\n").dataUsingEncoding($.NSNEXTSTEPStringEncoding));
    }
}

Note that I've added a line break at the end of each string—you may want to customize this behavior to meet your needs.

  • Grate! But some data should be unwrapped before output: console.log(ObjC.unwrap(app.bundleIdentifier)) – basil Nov 11 '18 at 7:22

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