更新状态时,我收到以下错误消息noteList.map is not a function
我有以下设置
src/pages/index.js
我的 DragDropContainer 正在安装的位置
const Index = ({ data, location }) => {
// instantiate a map of notes
const noteMap = new Map()
for (const brainNote of data.allBrainNote.nodes) {
const key = "/" + brainNote.slug
noteMap.set(key, brainNote)
}
return (
<Provider noteMap={noteMap} openNotes={[data.brainNote]}>
<DragDropContainer location={location}></DragDropContainer>
</Provider>
)
}
src/components/DragDropContainer.js
import React, { useContext } from "react"
import { DragDropContext } from "react-beautiful-dnd"
import ColumnDroppable from "../components/columnDroppable"
import { Consumer, Context } from "../utils/notesContext"
...
const DragDropContainer = ({ location }) => {
const notesContext = useContext(Context)
const { openNotes, setOpenNotes } = notesContext
...
return (
<div>
<div>
<div style={{ display: "flex" }}>
<DragDropContext onDragEnd={onDragEnd}>
<Consumer>
{context => (
<div>
{context.openNotes.map((noteList, ind) => (
<ColumnDroppable
key={ind}
index={ind}
noteList={noteList}
location={location}
/>
))}
</div>
)}
</Consumer>
</DragDropContext>
</div>
</div>
</div>
)
}
export default DragDropContainer
src/components/columnDroppable.js
const ColumnDroppable = ({ index, noteList, location }) => {
return (
<Droppable key={index} droppableId={`${index}`}>
{provided => (
<div ref={provided.innerRef} {...provided.draggableProps}>
{noteList.map((note, noteIdx) => ( // when updated this line throws an error
<NoteContainer
key={note.title}
title={note.title}
note={note}
noteId={note.title}
location={location}
slug={note.slug}
noteIdx={noteIdx}
></NoteContainer>
// <Note key={note.id} title={note.title} note={note} note noteIdx={noteIdx} />
))}
{provided.placeholder}
</div>
)}
</Droppable>
)
}
ColumnDroppable.propTypes = {
index: PropTypes.node.isRequired,
}
export default ColumnDroppable
src/utils/notesContext.js
export const Context = createContext({})
export const Provider = props => {
const { noteMap: initNoteMap, openNotes: initNote, children } = props
const [noteMap, setNoteMap] = useState(initNoteMap)
const [openNotes, setOpenNotes] = useState([initNote]) // openNotes is a 2D array
const setNoteAsOpen = slug => {
// note map has the key set to the slug of a note
const isNoteAlreadyOpen = openNotes.some(note => {
return note.slug === slug.slice(1)
})
if (isNoteAlreadyOpen) return // note is already open
const openingNote = noteMap.get(slug)
setOpenNotes([...openNotes, openingNote])
}
const notesContext = {
noteMap,
setNoteMap,
openNotes,
setOpenNotes,
setNoteAsOpen,
}
return <Context.Provider value={notesContext}>{children}</Context.Provider>
}
export const { Consumer } = Context
src/components/CustomLinkToDraggable.js
这是调用 setNoteAsOpen() 的地方
...
export const LinkToDraggableNote = React.forwardRef(
({ to, onClick, onMouseLeave, onMouseEnter, ...restProps }, ref) => {
const notesContext = useContext(Context)
const { openNotes, setNoteAsOpen } = notesContext
const onClickHandler = ev => {
console.log("within onclick handler")
ev.preventDefault()
setNoteAsOpen(to)
}
...
return (
<Link
{...restProps}
to={to}
ref={ref}
onClick={onClickHandler}
onMouseEnter={onMouseEnterHandler}
onMouseLeave={onMouseLeaveHandler}
/>
)
在setNoteAsOpen()
被调用之后,我注意到noteList
ColumnDroppable 仍然是数组类型,但不是 100% 抛出错误的原因。
我还注意到,在被调用setNoteAsOpen()
后openNotes
状态仍然相同。setOpenNotes()
好像setOpenNotes()
没有更新状态。我不确定这是否相关或导致问题,但我想我也会指出这一点。
提前致谢!