getValue () {
    if (this.type === 'array') {
      const arr = []
      this.childs.forEach(child => {
        arr.push(child.getValue())
      })
      return arr
    } else if (this.type === 'object') {
      const obj = {}
      this.childs.forEach(child => {
        obj[child.getField()] = child.getValue()
      })
      return obj
    } else {
      if (this.value === undefined) {
        this._getDomValue()
      }

      return this.value
    }
  }
Get value. Value is a JSON structure
@return {*} value