[英]How to modify array within object in react component state
我的應用程序中有以下狀態:
const [activeChats, setActiveChats] = useState([
{
id: 1,
name: 'Luciana Gutierrez',
role: 'HR Manager',
avatar: avatar2,
messages: [
{
content: 'Hola Luciana! Tuviste alguna novedad?',
received: false,
date: '9:45 AM'
},
{
content: 'Hola John! Todavía no...',
received: true,
date: '10:19 AM'
},
{
content: 'Si tengo alguna otra novedad te comento. Gracias!',
received: true,
date: '10:20 AM'
}
]
},
{
id: 2,
name: 'Micaela Alvarez',
role: 'Marketing Manager',
avatar: avatar1,
messages: [
{
content: 'Hola John! Entre qué horarios podrías hoy tener la meeting?',
received: true,
date: '9:45 AM'
},
{
content: 'Hola Micaela! Muy bien. Yo puedo de 10 a 17 hs.',
received: false,
date: '10:05 AM'
},
{
content: 'Dale, agendé la meeting para hoy a las 14hs.',
received: true,
date: '10:15 AM'
}
]
},
{
id: 3,
name: 'Manuel Hoffman',
role: 'Business Manager',
avatar: avatar3,
messages: [
{
content: 'Gracias por la reunión de ayer, Manu, fue muy productiva!',
received: false,
date: '9:35 AM'
},
{
content: 'Gracias a vos!',
received: true,
date: '9:37 AM'
}
]
}
])
而且我只想通過在每個對象的消息鍵中添加更多項目來修改它,而保持狀態的其余部分保持原樣。
例如,假設我向第一個對象添加了兩條新消息。 狀態應該是這樣的:
const [activeChats, setActiveChats] = useState([
{
id: 1,
name: 'Luciana Gutierrez',
role: 'HR Manager',
avatar: avatar2,
messages: [
{
content: 'Hola Luciana! Tuviste alguna novedad?',
received: false,
date: '9:45 AM'
},
{
content: 'Hola John! Todavía no...',
received: true,
date: '10:19 AM'
},
{
content: 'Si tengo alguna otra novedad te comento. Gracias!',
received: true,
date: '10:20 AM'
},
{
content: 'Example1',
received: true,
date: '10:21 AM'
},
{
content: 'Example2',
received: true,
date: '10:22 AM'
}
]
},
{
id: 2,
name: 'Micaela Alvarez',
role: 'Marketing Manager',
avatar: avatar1,
messages: [
{
content: 'Hola John! Entre qué horarios podrías hoy tener la meeting?',
received: true,
date: '9:45 AM'
},
{
content: 'Hola Micaela! Muy bien. Yo puedo de 10 a 17 hs.',
received: false,
date: '10:05 AM'
},
{
content: 'Dale, agendé la meeting para hoy a las 14hs.',
received: true,
date: '10:15 AM'
}
]
},
{
id: 3,
name: 'Manuel Hoffman',
role: 'Business Manager',
avatar: avatar3,
messages: [
{
content: 'Gracias por la reunión de ayer, Manu, fue muy productiva!',
received: false,
date: '9:35 AM'
},
{
content: 'Gracias a vos!',
received: true,
date: '9:37 AM'
}
]
}
])
我怎樣才能做到這一點? 我正在考慮擴展運算符,但我不確定如何將它與我擁有的嵌套一起使用。
您需要為setActiveStates
返回一個新數組,特別注意不要改變您正在更新的嵌套對象。 一個長期的方法是findIndex()
要更新的項目,然后使用此索引在相關項目之前和之后擴展數組的slice()
s,並檢索和克隆項目本身和任何嵌套對象屬性返回副本。
const newMessages = [{ content: 'new1', received: true, date: '10:21 AM' }, { content: 'new2', received: true, date: '10:22 AM' }];
const itemId = 1;
setActiveChats(prevState => {
const index = prevState.findIndex(({ id }) => id = itemId);
const item = prevState[index];
return [
...prevState.slice(0, index),
{ ...item, messages: [...item.messages, ...newMessages] },
...prevState.slice(index + 1)
];
});
使用嵌套結構執行此操作有點乏味,但應該可以:
setActiveChats(
activeChats.map((activeChat, idx) => {
// Add to the first entry
if (idx === 0) {
return {
...activeChat,
// assumes `newMessages` is an array of new messages
messages: [...activeChat.messages, ...newMessages]
};
}
return activeChat;
})
);
在此處查看完整的工作示例。
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