fix: Disable colors if the standard output is not a TTY

[crohasang]

Summary

Improved CLI color control to respect TTY status and NO_COLOR,
though console.log's automatic object coloring remains unaffected.

Related Issue

• closes Fedify CLI: Disable colors if the standard output is not a TTY #257

Changes

• Implemented NO_COLOR environment variable detection for global color control using @std/fmt/colors.setColorEnabled().
• Standardized color application by switching from @cliffy/ansi/colors to @std/fmt/colors and adapting the syntax (for example, colors.bold(colors.green(...))).
• The automatic color formatting applied by Deno's console.log() when printing JavaScript objects (for example, in fedify lookup command output) is a built-in runtime feature and remains unaffected by this change.

Additional Notes

1. Result image of 'deno task cli inbox' command in terminal.

2. Result image of 'deno task cli inbox > inbox.txt' command.

3. Result image of 'deno task cli lookup (handle) > lookup.txt'

The colors aren't disappearing because, I guess, Deno's console.log() automatically adds color when formatting JavaScript objects, a behavior not controlled by setColorEnabled().

update (KST 20250802 1634)

I created helper function using Deno.inspect in utils.js

export const colorEnabled: boolean = Deno.stdout.isTerminal() &&
  !Deno.env.has("NO_COLOR");

export function formatCliObjectOutputWithColor(
  obj: unknown,
  colors?: boolean,
): string {
  const enableColors = colors ?? colorEnabled;
  return Deno.inspect(obj, { colors: enableColors });
}

and applied it in several files.

I added 'colors' optional property because this function have to think about '-o' command in lookup. (Thanks to @2chanhaeng)

    const enableColors = colorEnabled && options.output === undefined;
    content = formatCliObjectOutputWithColor(content, enableColors);

Test Update

1. Result image of 'deno task cli lookup (handle) -o lookup.txt

2. Result image of 'deno task cli lookup (handle) > lookup.txt

3. Result image of 'deno task cli inbox > inbox.txt

[gemini-code-assist]

Summary of Changes

Hello @crohasang, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refines the command-line interface's color output by implementing a more robust and standard-compliant mechanism. It ensures that colors are automatically disabled when the output is not a terminal or when the NO_COLOR environment variable is present, achieved through a migration to Deno's standard library for color utilities and corresponding syntax updates across the CLI.

Highlights

• Improved CLI Color Control: The CLI now intelligently disables color output when the standard output is not a TTY (e.g., when redirecting to a file) or when the NO_COLOR environment variable is set. This enhances usability for scripting and environments where ANSI escape codes are undesirable.
• Color Library Migration: The project's color handling has been standardized by migrating from @cliffy/ansi/colors to @std/fmt/colors from the Deno standard library. This change involved updating all instances of color application syntax across the CLI codebase.
• Deno's console.log() Behavior: It's important to note that the automatic color formatting applied by Deno's console.log() when printing JavaScript objects (e.g., in fedify lookup command output) is a built-in runtime feature and remains unaffected by these changes, as it's not controlled by the setColorEnabled() function.

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[gemini-code-assist]

Code Review

This pull request does a great job of standardizing color handling in the CLI by migrating from @cliffy/ansi/colors to @std/fmt/colors. The implementation correctly disables colors when the output is not a TTY or when the NO_COLOR environment variable is set. The changes across the various command files are consistent with the new library's API.

I have one suggestion in cli/mod.ts to make the NO_COLOR check more robust by using Deno.env.has() instead of checking for undefined. This is a minor improvement for maintainability.

It's good that you've noted the limitation regarding Deno.inspect's color handling in the PR description. Overall, this is a solid improvement to the CLI's user experience.

[gemini-code-assist]

The current check for the NO_COLOR environment variable, Deno.env.get("NO_COLOR") === undefined, is functionally correct for now but could be more robust.

A more explicit way to check for the presence of an environment variable is by using Deno.env.has(). This makes the intent clearer and is less susceptible to potential changes in how Deno.env.get() handles edge cases (like empty strings) in future Deno versions.

Using !Deno.env.has("NO_COLOR") would improve readability and robustness.

const colorEnabled = Deno.stdout.isTerminal() && !Deno.env.has("NO_COLOR");

[crohasang]

Thanks for advice. I applied your feedback!

[github-actions]

The docs for this pull request have been published:

https://7ed287ec.fedify.pages.dev

[dahlia]

You could utilize the Deno.inspect() API which provides option colors: boolean. Under the hood, console.log() utilizes it.

[crohasang]

Thanks for advice! I made helper function using Deno.inspect and tried to control colors and it worked!

[2chanhaeng]

I read cli/lookup.ts and add log the file like this:

      // line 109
+    console.log(
+      {
+        where: "before inspect",
+        content,
+      },
+    );

    content = Deno.inspect(content, {
      colors: !(options.output),
    });

    const encoder = new TextEncoder();
    const bytes = encoder.encode(content + "\n");
+    console.log(
+      {
+        where: "after inspect",
+        content,
+      },
+    );

And I run deno task cli lookup @[email protected] > lookup.txt, then log like this.

{ isTerminal: false, colorEnabled: false }
{
  where: "before inspect",
  options: {
    cacheDir: "/root/.cache/fedify",
    firstKnock: "rfc9421",
    separator: "----"
  },
  colorEnable: false,
  content: Person {
    id: URL "https://hackers.pub/ap/actors/0197d646-c123-7ad4-a2f1-c6ff8a98fd2f",
    // ...
  }
}
{
  where: "after inspect",
  content: "Person {\n" +
    '  id: URL \x1b[32m"https://hackers.pub/ap/actors/0197d646-c123-7ad4-a2f1-c6ff8a98fd2f"\x1b[39m,\n' +
    '  name: \x1b[32m"
    // ...
}

So that means, somthing is wrong in content = Deno.inspect(content, { colors: !(options.output) });
I replace !(options.output) with !!(options.output), and the log after runned command like this:

{
  where: "before inspect",
  options: {
    cacheDir: "/root/.cache/fedify",
    firstKnock: "rfc9421",
    separator: "----"
  },
  colorEnable: false,
  content: Person {
    id: URL "https://hackers.pub/ap/actors/0197d646-c123-7ad4-a2f1-c6ff8a98fd2f",
    // ...
}
{
  where: "after inspect",
  content: "Person {\n" +
    '  id: URL "https://hackers.pub/ap/actors/0197d646-c123-7ad4-a2f1-c6ff8a98fd2f",\n' +
    // ...
}

So the problem is colors option of Deno.inspect.
And I read other changes, then I found setColorEnabled code, but getColorEnabled is not using.
So I changed the code like this:

    content = Deno.inspect(content, {
      colors: !(options.output) && colors.getColorEnabled(),
    });

And the log is perpect!
Therefore I suggest this change:

    content = Deno.inspect(content, {
      colors: !(options.output) && colors.getColorEnabled(),
    });

[github-actions]

The latest push to this pull request has been published to JSR and npm as a pre-release:

Package	Version	JSR	npm
@fedify/fedify	1.8.1-pr.341.1249+54907966	JSR	npm
@fedify/cli	1.8.1-pr.341.1249+54907966	JSR
@fedify/amqp	1.8.1-pr.341.1249+54907966	JSR	npm
@fedify/express	1.8.1-pr.341.1249+54907966	JSR	npm
@fedify/h3	1.8.1-pr.341.1249+54907966	JSR	npm
@fedify/nestjs	1.8.1-pr.341.1249+54907966		npm
@fedify/postgres	1.8.1-pr.341.1249+54907966	JSR	npm
@fedify/redis	1.8.1-pr.341.1249+54907966	JSR	npm
@fedify/testing	1.8.1-pr.341.1249+54907966	JSR	npm