cssinjs/jss

Extend function property values are converted to strings

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#1,134 opened on Jun 17, 2019

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 (0 comments) (2 reactions) (0 assignees)JavaScript (7,000 stars) (434 forks)batch import
bughelp wanted

Description

Expected behavior: A clear and concise description of what you expected to happen.

const styles = {
  linkCommon: {
    color: () => "orange"
  },
  link: {
    extend: "linkCommon"
  }
};

The link should be orange.

Describe the bug: A clear and concise description of what happend instead of the expected behavior.

The function is being converted to a string before being inserted into the DOM.

image

Codesandbox link:

Playground: https://codesandbox.io/embed/core-jss-playground-ef0j4

Versions (please complete the following information):

  • jss: 10 alpha 18
  • jss-preset-default: 10 alpha 18
  • Browser Chrome 75
  • OS: OX X

Feel free to add any additional versions which you may think are relevant to the bug.

Not to be confused with https://github.com/cssinjs/jss/issues/479

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.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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 JSSUnderstanding of how CSS in JS resolves styles
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate how the `extend` property merges styles when values are functions. Look at the source files in the JSS repository, particularly the style merging logic (e.g., `src/`). The issue shows that when a function is used as a value in an extended style, it gets converted to a string. Compare with the handling of functions in non extended styles. Check if there is a test case for similar scenarios and consider adding one. The playground link suggests the code uses jss preset default; ensure the fix works with the default preset.