@coreui/coreui-pro/js/src/utilities/get-css-custom-properties.js

UI Kit built on top of Bootstrap 4

/**
 * --------------------------------------------------------------------------
 * CoreUI Utilities (v2.1.14): get-css-custom-properties.js
 * Licensed under MIT (https://coreui.io/license)
 * @returns {string} css custom property name
 * --------------------------------------------------------------------------
 */
const getCssCustomProperties = () => {
  const cssCustomProperties = {}
  const sheets = document.styleSheets
  let cssText = ''
  for (let i = sheets.length - 1; i > -1; i--) {
    const rules = sheets[i].cssRules
    for (let j = rules.length - 1; j > -1; j--) {
      if (rules[j].selectorText === '.ie-custom-properties') {
        cssText = rules[j].cssText
        break
      }
    }
    if (cssText) {
      break
    }
  }

  cssText = cssText.substring(
    cssText.lastIndexOf('{') + 1,
    cssText.lastIndexOf('}')
  )

  cssText.split(';').forEach((property) => {
    if (property) {
      const name = property.split(': ')[0]
      const value = property.split(': ')[1]
      if (name && value) {
        cssCustomProperties[`--${name.trim()}`] = value.trim()
      }
    }
  })
  return cssCustomProperties
}

export default getCssCustomProperties