Colors not displayed when child process output is piped

[bcaudan]

Hi,

It seems that colors.js does not work when a child process output is piped.

For example, if I try to execute this code:

require('colors')

console.log('\x1b[31mansi\x1b[0m'); // red with ansi escaped codes
console.log('colors'.red);          // red with colors.js

With this runner:

var spawn = require('child_process').spawn;

var child = spawn('node', ['test.js'], { stdio: 'pipe' });

child.stdout.pipe(process.stdout)

Only the first line is in red.
But if I change the stdio option to 'inherit' then both lines are in red.

Is there a way that colors.js also works when output is piped?

[derrickpelletier]

@bcaudan when you spawn your script, include an argument for --color.

colors.js is set to automatically detect if it is on a TTY, if it's being piped it assumes no and strips out colors.

[bcaudan]

In my real use case (see referenced issue), I don't have control on how the script is spawn. Is there a way to force it programatically?

[bcaudan]

OK, I figured it out. I can set the enabled property like this:

var colors = require('colors');
colors.enabled = true;

And then colors are displayed!

Thanks for your help @derrickpelletier.

[lixinliang]

Thank godness!
I find what I need here!
It's missing argument --color!

I believed that it's the shelljs(child process module)'s problem.
Or there was something wrong I wrote.

I had no idea of the required argument --color!

[ORESoftware]

anyone know how to do this with bash?

in my child process, I have echo -e "some control chars";

they colors/styling show up in the child, but when the parent inherits the stdout, the colors don't show up.

[Akryum]

You can try setting this env variable: FORCE_COLOR=1