stylelint/src/rules/keyframe-declaration-no-important/index.js

Modern CSS linter

import {
  report,
  ruleMessages,
  validateOptions,
} from "../../utils"

export const ruleName = "keyframe-declaration-no-important"

export const messages = ruleMessages(ruleName, {
  rejected: "Unexpected !important",
})

export default function (actual) {
  return (root, result) => {
    const validOptions = validateOptions(result, ruleName, { actual })
    if (!validOptions) { return }

    root.walkAtRules(/^keyframes$/i, atRuleKeyframes => {
      atRuleKeyframes.walkDecls(decl => {
        if (!decl.important) { return }
        report({
          message: messages.rejected,
          node: decl,
          word: "important",
          result,
          ruleName,
        })
      })
    })
  }
}