rofrischmann/fela

import { isUnitlessProperty as defaultIsUnitlessProperty } from 'css-in-js-utils'
import isPlainObject from 'isobject'

function addUnitIfNeeded(value, propertyUnit) {
  const valueType = typeof value
  /* eslint-disable eqeqeq */
  if (
    (valueType === 'number' ||
      (valueType === 'string' && value == parseFloat(value))) &&
    value != 0
  ) {
    return value + propertyUnit
  }
  /* eslint-enable */
  return value
}

function addUnit(style, defaultUnit, propertyMap, isUnitlessProperty) {
  for (const property in style) {
    if (!isUnitlessProperty(property)) {
      const cssValue = style[property]
      const propertyUnit = propertyMap[property] || defaultUnit

      if (isPlainObject(cssValue)) {
        style[property] = addUnit(
          cssValue,
          defaultUnit,
          propertyMap,
          isUnitlessProperty
        )
      } else if (Array.isArray(cssValue)) {
        style[property] = cssValue.map((val) =>
          addUnitIfNeeded(val, propertyUnit)
        )
      } else {
        style[property] = addUnitIfNeeded(cssValue, propertyUnit)
      }
    }
  }

  return style
}

function createOptimized(defaultUnit, propertyMap, isUnitlessProperty) {
  return (props) => {
    if (!isUnitlessProperty(props.property)) {
      const valueType = typeof props.value
      /* eslint-disable eqeqeq */
      if (
        (valueType === 'number' ||
          (valueType === 'string' && props.value == parseFloat(props.value))) &&
        props.value != 0
      ) {
        const currentUnit = propertyMap[props.property] || defaultUnit
        props.value += currentUnit
      }

      // handle arrays
      if (Array.isArray(props.value)) {
        const propertyUnit = propertyMap[props.property] || defaultUnit

        props.value = props.value.map((value) =>
          addUnitIfNeeded(value, propertyUnit)
        )
      }
    }

    return props
  }
}

export default function unit(
  defaultUnit = 'px',
  propertyMap = {},
  isUnitlessProperty = defaultIsUnitlessProperty
) {
  function unitPlugin(style) {
    return addUnit(style, defaultUnit, propertyMap, isUnitlessProperty)
  }

  unitPlugin.optimized = createOptimized(
    defaultUnit,
    propertyMap,
    isUnitlessProperty
  )

  return unitPlugin
}