Nvm: Configurable output colors

[vestacp]

Here is my output on ubuntu:

I changed my "LS_COLORS", it takes effect on ls command. But the the color of nvm ls is still dark blue.

How can I change it to a readable color ?

[ljharb]

I use a white background, so I don't notice this.

Using LS_COLORS is an interesting idea. What have you set yours to?

[vestacp]

This is my color:

LS_COLORS=$LS_COLORS:'di=0;35:' ; export LS_COLORS

[ljharb]

so, after researching LS_COLORS I don't think that's the right thing to respect - "installed node version", "not installed node version", "active node version", "alias" don't really have analogues to what ls outputs.

That said, if you can think of a sensible way to combine a setting for those 5 colors, i'd be happy to consider making them configurable.

[vestacp]

I don't care which colors they should respect to, but please make it more readable. I think in most cases, the background of the shell is black.
I wonder why it's in darkblue? Any reason? If not, please change it to any other color that is readable.

[vestacp]

And, I don't think it's a "feature requests".

[ljharb]

The feature request would be to customize the colors. It's been these colors for the entirety of nvm's existence, and nobody's once brought it up before now, so I don't think "in most cases" is a credible claim, either for terminal background color or "unreadable". tbh, in your screenshot, the white doesn't even look white (it seems to have shades of green in it) - perhaps your OS's colors can be tweaked?

[vestacp]

The OS is in a vm. The raw Ubuntu 15.
The snapshot was taken from my host machine.
Anyone can try it in a few minutes.

[ljharb]

Sure, I've tried it just now, and it looks perfectly readable on a black background to me.

I'll leave this open as a feature request for nvm ls color customization, since color perception is variable and subjective - otherwise, feel free to close it.

[vestacp]

Could you please paste a snapshot?

[ljharb]

Sure, here's 4 of the color profiles in the default Mac OS X terminal:

[ghost]

I'd like to see the ability to remove color output altogether. Using the output of NVM in a scripted way is difficult because the output has bash color escape characters in it. For example, applying changes to all installed versions of Node, I get errors like:

N/A version is not installed...
bash: line 1: $'v6.3.1\E[0m': command not found
bash: line 2: $'system\E[0m': command not found

This is after a naive (i.e. simply parsed) loop on all the installed versions of node, e.g.

for v in $(nvm list node 2>&1 | awk '{print $NF}'); do nvm use "${v}"; done

Alternatively, provide a machine-readable output option.

[ljharb]

@jsilverman-blispay I'd like to add --no-color to every command, but in the meantime, you should be able to set the TERM environment variable to "dumb" to strip colors?

[ghost]

I will try that. Thanks

[ghost]

Tried it; it didn't work.

Incidentally, my workaround is this:

for v in $(nvm list node 2>&1 | grep -v system | sed 's/\x1B\[[0-9;]*[a-zA-Z]//g' | awk '{print $NF}' ); do nvm use "${v}"; done

Note the "sed" part, which removes the non-printing escape characters:

sed 's/\x1B\[[0-9;]*[a-zA-Z]//g'

[ljharb]

@jsilverman-blispay what version of nvm are you using? if you update to the latest, TERM=dumb should work.

[ljharb]

@jsilverman-blispay the next version will support --no-colors in nvm alias, nvm ls, and nvm ls-remote - per 0678652bd314726e63ac5e137e9fca538994d1f4

[gitburd]

@naomiquinones and I are going to work on this as our next issue.

[ljharb]

@gitburd that's great; but it's very unclear what this feature would look like. Before making a PR, let's workshop things here?

[gitburd]

@ljharb @naomiquinones It seems like the concern is mostly for dark background displays. The default colors could be what they are now and there could be an alternative color configuration with lighter text colors that might show up better on dark backgrounds. There could be a display flag that would allow users to switch between color configurations.

[ljharb]

That's certainly a possibility; however i assume users would want configurability of individual colors. It's fine if we start with just a flag, but I'd want the design for full configurability to be thought about first, to ensure a smooth evolution.

[naomiquinones]

Hi @ljharb, after discussing with @gitburd, it seems like we could set a flag --setcolors and either the user passes in an array of colors (e.g. nvm --setcolors bold-cyan magenta dim-yellow green), or when the user calls nvm --setcolors, we go through a set of prompts to have them choose from a set of available colors. We could store that info in some kind of configuration file or variable that contains those colors. There is already an NVM_COLORS, so maybe an array called NVM_USER_COLORS?

[ljharb]

That general approach seems good; prompts would have to be careful to not run in a non-TTY, and that array notation i don't think is likely to work (multiple arguments would be passed like --x=a --x=b --x=c or -x a -x b -x c, or it could maybe be --x=a,b,c altho comma-separated is uncommon.

[ljharb]

Also note that POSIX doesn't have arrays (except for invocation arguments).

[gitburd]

@ljharb @naomiquinones Would it make sense to do a prompt for each color and enter them one a time? How many are used? 5?

[Yash-Singh1]

@gitburd I think nvm assumes that your shell is non-interactive. That would not include prompts.

[gitburd]

@ljharb @Yash-Singh1 @naomiquinones

multiple arguments would be passed like --x=a --x=b --x=c or -x a -x b -x c

so could something like this work: --display -a cyan -b yellow -c green -d magenta? or using the color codes instead of the words?

[ljharb]

Hmm - typically command line arguments are either positional, or not; the non-positional ones are in the form -x y or --x=y. iow, each color would need to be its own independent parameter.

[gitburd]

--color-one=blue, --color-two=green, --color-three=red?

[Yash-Singh1]

I think cmatrix had a similar problem. Here is there man page:

 Usage: cmatrix -[abBcfhlsmVx] [-u delay] [-C color]
 -a: Asynchronous scroll
 -b: Bold characters on
 -B: All bold characters (overrides -b)
 -c: Use Japanese characters as seen in the original matrix. Requires appropriate fonts
 -f: Force the linux $TERM type to be on
 -l: Linux mode (uses matrix console font)
 -L: Lock mode (can be closed from another terminal)
 -o: Use old-style scrolling
 -h: Print usage and exit
 -n: No bold characters (overrides -b and -B, default)
 -s: "Screensaver" mode, exits on first keystroke
 -x: X window mode, use if your xterm is using mtx.pcf
 -V: Print version information and exit
 -u delay (0 - 10, default 4): Screen update delay
 -C [color]: Use this color for matrix (default green)
 -r: rainbow mode
 -m: lambda mode

They didn't do the --x=y option. I think that most people are used to the -x y option that is shown as the -C [color] option inside the cmatrix command. We should use the same way. Prompts should not be used because nvm does not require your shell to be interactive. Also, the --x=y is a bit messier because if someone writes in -x = y it won't be accepted without more complex computing on the arguments. On the other hand, -x y with a bunch of spaces are between the two of them will be accepted because parameters are never null unless they aren't given. Because of these reasons, I suggest -x y. I have not seen a CLI that allows configuration for multiple colors. That can quickly get complicated, messy, and unnecessary. The best option would be to give configuration to only one color. If that is your goal then the best option would be to do something like -C [colors]. The [colors] should be in the following form: red,blue,green. If you want color2 to be auto then you can do: red,auto,green. I am on Ubuntu 20.04 and nvm ls outputs the following:

->      v14.7.0
         system
default -> node (-> v14.7.0)
node -> stable (-> v14.7.0) (default)
stable -> 14.7 (-> v14.7.0) (default)
iojs -> N/A (default)
unstable -> N/A (default)
lts/* -> lts/erbium (-> N/A)
lts/argon -> v4.9.1 (-> N/A)
lts/boron -> v6.17.1 (-> N/A)
lts/carbon -> v8.17.0 (-> N/A)
lts/dubnium -> v10.22.0 (-> N/A)
lts/erbium -> v12.18.3 (-> N/A)

I have not customized the $LS_COLORS environment variables. It is probably because I have a different Ubuntu version.

[mkcode]

Would a colon delimited array be acceptable?

After looking at this for a while, we could easily rename the NVM_COLORS to NVM_NUM_COLORS because it is only used as a function local variable here: https://github.com/nvm-sh/nvm/blob/9dc6f3e4a548658218d5c93bb55d0913cc65f5bf/nvm.sh#L72-L78

This would allow us to use the same colon delimited array format as a NVM_COLORS environment variable and as a --colors argument. Documenting this format would be important as well.

Example usages:

export NVM_COLORS=red:blue:green:magenta:cyan

or

nvm --colors red:blue:green:magenta:cyan

[Yash-Singh1]

Yes, the comma method that I gave was just a suggestion. I think that colon (:) would actually be better! :+1:

[ljharb]

Even using a comma seems pretty rare and unidiomatic; using a colon seems wildly unintuitive and confusing.

[naomiquinones]

What about eliminating the delimiter and always passing the colors in with a set order the way the LSCOLORS environment variable is set (e.g. LSCOLORS=gxfxCxgxBxGegcbhahechd) or the way hex colors are set for CSS/HTML (e.g. color=#b9feea)?

Example usage:

export NVM_COLORS=cyanyellowbluegreygreen

or

export NVM_COLORS=3633343732

or

nvm --colors cyanyellowbluegreygreen

[ljharb]

Matching what LS_COLORS does seems pretty defensible!

[gitburd]

@ljharb
@naomiquinones and I made a branch with a suggested change to the help menu that uses set-colors in a LS_COLORS-like string format and can proceed with adding functionality if you approve.
https://github.com/gitburd/nvm/commit/56dfb3c7825ab768431566027cb14160f7ba81a9

[naomiquinones]

@ljharb we are also thinking of displaying the color options in their colors so the user can see immediately what the options would look like on their screen.

[naomiquinones]

@ljharb,
@gitburd and I came up with the following way of displaying the colors in the help section:
https://github.com/naomiquinones/nvm/blob/8867948fac3e923877aaecd997ad01df7d2c2495/nvm.sh#L2420-L2428

[ljharb]

Hmm, looks nice - however, it will have to use nvm_has_colors and skip the colors when that's false, and every command would need to support a --no-colors option as well. It'd be useful to also show what the default is, and i'd be curious to see what nvm set-colors' output looked like :-)

[Yash-Singh1]

I noticed that LS_COLORS was a bunch of wildcards with an ANSI-Color. What wildcards will nvm match?