function normalizeRowColumn(str) {
  let normalized = parser(str).nodes.reduce((result, node) => {
    if (node.type === 'function' && node.value === 'repeat') {
      let key = 'count'

      let [count, value] = node.nodes.reduce(
        (acc, n) => {
          if (n.type === 'word' && key === 'count') {
            acc[0] = Math.abs(parseInt(n.value))
            return acc
          }
          if (n.type === 'div' && n.value === ',') {
            key = 'value'
            return acc
          }
          if (key === 'value') {
            acc[1] += parser.stringify(n)
          }
          return acc
        },
        [0, '']
      )

      if (count) {
        for (let i = 0; i < count; i++) {
          result.push(value)
        }
      }

      return result
    }
    if (node.type === 'space') {
      return result
    }
    return result.concat(parser.stringify(node))
  }, [])

  return normalized
}
normalize the grid-template-rows/columns values
@param  {String} str grid-template-rows/columns value
@return {Array} normalized array with values
@example
let normalized = normalizeRowColumn('1fr repeat(2, 20px 50px) 1fr')
normalized // <= ['1fr', '20px', '50px', '20px', '50px', '1fr']