code: function TRANSITION_PROPERTY_VALIDATOR(v) {
    v = (v || '').toString()
    v = util.hyphenedToCamelCase(v)
  
    for (var prop in validatorMap) {
      if (prop === v) {
        return {value: v}
      }
    }
  
    return {
      value: null,
      reason: function reason(k, v, result) {
        return 'ERROR: property value `' + v + '` is not supported for `' + util.camelCaseToHyphened(k) + '` (only css property is valid)'
      }
    }
  }
docs: transition-property: only css property is valid
  
  @param {string} v
  @return {function} a function to return
  - value: string|null
  - reason(k, v, result)