cssinjs/jss

Warning: [JSS] Function values inside function rules are not supported.

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#1474 opened on Mar 22, 2021

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 (3 comments) (0 reactions) (0 assignees)JavaScript (7,000 stars) (434 forks)batch import
bughelp wanted

Description

Expected behavior: Do not show warning, because it works well.

Describe the bug: For some reasons I wrote my code like this:

const useStyles = createUseStyles(({ colors, variables, breakpoints }) => ({
  // above line get the theme variables
  cropperRoot: {
    margin: [0, -variables.gutter],
  },
  cropContainer: ({ cropWrapSize = 250 }) => ({
    // above line get the variables from passed props to useState({ cropWrapSize })
    height: cropWrapSize + 44 + 60,
    padding: [44, 0, 60],
    overflow: 'hidden',
    background: colors.backgroundIcon,
  }),

Now I'm faced to this warning:

Warning: [JSS] Function values inside function rules are not supported.

Versions (please complete the following information):

  • jss: "^10.5.1",
  • Browser [e.g. chrome, safari]: 89.0.4
  • OS [e.g. Windows, macOS]: Big Sur 11.2.3 Feel free to add any additional versions which you may think are relevant to the bug.

Why this Warning is shown?

Contributor guide

Tech stack
javascriptcss
Domain
frontend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Basic knowledge of JSSCSS in JS concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the source of the warning 'Function values inside function rules are not supported' in JSS. The warning appears when using a function rule that itself returns an object with function values (e.g., cropContainer: ({ cropWrapSize }) => ({ height: cropWrapSize + ... })). Check the JSS source code in the 'src/' directory for the warning message and the logic that triggers it. Examine if this is intended behavior or a false positive. Review any related issues or comments, such as those in the linked issue #1474, for additional context.