Method walk

lib/container.js:311–325

(callback)

  }

  walk(callback) {
    return this.each((child, i) => {
      let result
      try {
        result = callback(child, i)
      } catch (e) {
        throw child.addToError(e)
      }
      if (result !== false && child.walk) {
        result = child.walk(callback)
      }

      return result
    })
  }

  walkAtRules(name, callback) {
    if (!callback) {