.display and .toString different behavior on nextjs in dev and build mode

[star-over]

Trying to use color.display({"format": "hex"}) as well as .toString({"format": "hex"}) in nextjs v13.
In dev it works fine, outputs #111 for example, but in prod mode it outputs color(srgb 0.0667 0.0667 0.0667) when running bundle after next build.
So I use this method to get the same result in dev and in prod mode Color.defaults.display_space.formats.hex.serialize(color.coords).
Is there any "correct" solution to output hexadecimal representation of colour (#123456)?

[LeaVerou]

This sounds very similar to an issue we had recently and fixed in #239
Could you please make sure you’re using v0.4.2 of Color.js?

[star-over]

Pretty shure.
"colorjs.io": "^0.4.2" - record in package.json

[nick-inkeep]

@LeaVerou any update on this? Facing same issue.

[LeaVerou]

Hey, sorry this slipped through the cracks. Could you make a reduced testcase that I could look at and play with (e.g. on stackblitz or something)?

[sarah-inkeep]

Hi @LeaVerou! I made a reduced test case here. When it's running in dev mode (next dev) you'll see the color is in the expect hex format, but if you run next build && next start and then refresh, it outputs as color(srgb 0.3216 0.1843 0.7882).

[jh3y]

Can confirm, having this issue too, albeit slightly differently.

let color = new Color('hsl(0 100% 50%)')
color.to('p3').toString() // Dev = color(display-p3 0.9175 0.2003 0.1386)
color.to('p3').toString() // Prod = color(p3 0.9175 0.2003 0.1386)

Works fine for other formats I've found 🤔

[lloydk]

I took a look at this, the reduced test case was super helpful.

When the test app is run in dev mode the code for the page is run in the browser and works correctly.

In production mode (next build && next start) Next.js generates static pages and the code for the page is run as part of the build process and does not run correctly.

The color.js code that is failing is the assignment of the format variable:

color.js/src/serialize.js

Lines 26 to 28 in b896c0d

	format = color.space.getFormat(format)
	?? color.space.getFormat("default")
	?? ColorSpace.DEFAULT_FORMAT;

If you print out the value of the format variable (pay attention to the location of the console.log statement) the value of format is "hex" which is the value that was passed into the serialize function.

	format = color.space.getFormat(format)
	       ?? color.space.getFormat("default")
	       ?? ColorSpace.DEFAULT_FORMAT;

	inGamut ||= format.toGamut;

	let coords = color.coords.slice(); // clone so we can manipulate it

	if (inGamut && !checkInGamut(color)) {
		// FIXME what happens if the color contains NaNs?
		coords = toGamut(clone(color), inGamut === true ? undefined : inGamut).coords;
	}

	console.log(`format is ${format}`);

If you move the console.log statement just below the assignment of the format variable the code runs correctly.

	format = color.space.getFormat(format)
	       ?? color.space.getFormat("default")
	       ?? ColorSpace.DEFAULT_FORMAT;
	console.log(`format is ${format}`);

	inGamut ||= format.toGamut;

If you access a property of format right after the assignment the code runs correctly.

	format = color.space.getFormat(format)
	       ?? color.space.getFormat("default")
	       ?? ColorSpace.DEFAULT_FORMAT;

	let x = format.type;

If you replace the nullish coalescing operators with if/else statements the code runs correctly.

	format = color.space.getFormat(format);

	if (!format) {
		format = color.space.getFormat("default");
	}
	else {
		if (!format) {
			format = ColorSpace.DEFAULT_FORMAT;
		}
	}

This also works and maybe should be the preferred workaround?

	format = color.space.getFormat(format) ?? color.space.getFormat("default");

	if (!format) {
		format = ColorSpace.DEFAULT_FORMAT;
	}

TLDR: The issue appears to be Next.js bug but there are some ways to work around the issue.

[LeaVerou]

Thank you so much for tracking it down @lloydk! Should we close this issue then?

[lloydk]

Thank you so much for tracking it down @lloydk! Should we close this issue then?

Up to you, we can either close the issue or I can create a PR for one of the work arounds.

[svgeesus]

Maybe we should have a FAQ listing these sorts of known issues and workarounds?

[lloydk]

Changing the code from

	inGamut ||= format.toGamut;

	let coords = color.coords.slice(); // clone so we can manipulate it

to

	let coords = color.coords.slice(); // clone so we can manipulate it

	inGamut ||= format.toGamut;

seems to work for me so I'll create a PR for that change.