如何在 Elm 中返回元素列表

Question

我正在尝试从一个简单的ELM数组中构建元素列表。预期结果只是一个元素列表，其中第一项为1，第二项为2，依此类推。

import Html exposing (..)
import Html.Attributes exposing (class, id)
import List exposing (map)

theArray = [1,2,3,4,5,6]

createListItem item =
  li [] [ text (toString item)]

buildList collection =
  map createListItem collection

builtList = ul [] [(buildList theArray)]

main = 
  builtList

但是我一直在第十三行遇到编译器错误。我尝试将地图元素注释为html类型，但我不知道该怎么做。

The 2nd argument to function `ul` is causing a mismatch.

 *13| builtList = ul [] [(buildList theArray)]*

Function `ul` is expecting the 2nd argument to be:

    List VirtualDom.Node

But it is:

    List (List Html)

- whatoncewaslost

Answer 1

buildList 已经返回了一个类型为 List Html 的值，因此您不需要在 (buildList theArray) 周围加括号。将第 13 行改为：

builtList = ul [] (buildList theArray)

- Chad Gilbert