Terminal styling (control chars) using the chalk NPM module

Question

Say I have this:

//exp.js
const chalk = require('chalk');
console.log(chalk.red('foobar'));

and then I run at the command line:

node exp.js | cat

In all the cases I have seen, the colors won't show up. Does anyone know why? Is there a way to get the colors to show up? Am I doing something wrong?

My only guess is that the chalk library "turns off" the string styling when the processes are hooked up in a pipe?

For example:

Here's the chalk library source - https://github.com/chalk/chalk/blob/master/index.js — Alexander Mills, Oct 14 '17 at 06:36
I prefer to fill up the comments, and keep the question tidy — Alexander Mills, Oct 14 '17 at 06:37
They should not. Comments on questions are reserved to others. I edited your question to add the link, but you should have done that. — Basile Starynkevitch, Oct 14 '17 at 06:38
BTW, that library (which I am discovering) *documents* that it "auto-detects color support". I suggest to add an issue in their github. — Basile Starynkevitch, Oct 14 '17 at 06:42
Here is the issue on Github: https://github.com/chalk/chalk/issues/212 — Alexander Mills, Oct 14 '17 at 07:04
That issue URL should also go into the question. Basically, you should forbid yourself to comment your own questions. — Basile Starynkevitch, Oct 14 '17 at 07:07

score 2 · Accepted Answer · answered Oct 14 '17 at 09:38

2

As per the fine manual:

$ node exp.js --color | cat
$ env FORCE_COLOR=1 node exp.js | cat

Or:

//exp.js
process.env.FORCE_COLOR = '1';
const chalk = require('chalk');
console.log(chalk.red('foobar'));

answered Oct 14 '17 at 09:38

robertklep

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oh yes, that must be it – Alexander Mills Oct 14 '17 at 10:09

Terminal styling (control chars) using the chalk NPM module

1 Answers1