notes/node_modules/stylelint/lib/utils/isValidFontSize.js

/* @flow */
"use strict"

const keywordSets = require("../reference/keywordSets")
const valueParser = require("postcss-value-parser")

/**
 * Check if a word is a font-size value.
 */
module.exports = function (word/*: string*/)/*: boolean*/ {
  if (!word) {
    return false
  }

  if (keywordSets.fontSizeKeywords.has(word)) {
    return true
  }

  const numberUnit = valueParser.unit(word)
  if (!numberUnit) {
    return false
  }

  const unit = numberUnit.unit

  if (unit === "%") {
    return true
  }
  if (keywordSets.lengthUnits.has(unit.toLowerCase())) {
    return true
  }

  return false
}