根据 ID 在 React 中编辑对象数组中的属性

Question

我在新的"上下文 API"中创建了一个对象数组，如下所示......

const reducer = (state, action) => {
switch (action.type) {
case "DELETE_CONTACT":
return {
...state,
contacts: state.contacts.filter(contact => {
return contact.id !== action.payload;
})
};
default:
return state;
}
};
export class Provider extends Component {
state = {
contacts: [
{
id: 1,
name: "John Doe",
email: "[e-mail]",
phone: "01027007024",
show: false
},
{
id: 2,
name: "Adam Smith",
email: "[e-mail]",
phone: "01027007024",
show: false
},
{
id: 3,
name: "Mohammed Salah",
email: "[e-mail]",
phone: "01027007024",
show: false
}
],
dispatch: action => {
this.setState(state => reducer(state, action));
}
};
render() {
return (
<Context.Provider value={this.state}>
{this.props.children}
</Context.Provider>
);
}
}

我想在"reducer"中创建一个操作，允许我根据每个联系人的 id 编辑每个联系人的"show"属性，我将作为有效负载传递给操作，我该怎么做？

Answer 1

为了避免数组突变并在编辑联系人时保留元素位置，您可以执行以下操作：

case "EDIT_CONTACT":
const { id, show } = action.payload;
const contact = { ...state.contacts.find(c => c.id === id), show };
return {
...state,
contacts: state.contacts.map(c => {return (c.id !== id) ? c : contact;})        
};

Answer 2

你可以找到联系人，通过使用spread避免突变，设置show的新值：

case "EDIT_CONTACT":
const { id, show } = action.payload; // Assume id and show are in action.payload
const contact = { ...state.contacts.find(c => c.id === id), show };
return {
...state,
contacts: [...state.contacts.filter(c => c.id !== id), contact]
};

如果顺序很重要：

const { id, show } = action.payload; 
const contact = { ...state.contacts.find(c => c.id === id), show };
const index = state.contacts.findIndex(c => c.id === id);
return {
...state,
contacts = [ ...state.contacts.slice(0, index), contact, ...state.contacts.slice(index + 1)];
}