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VistasHow to return an object conditionally
I'm working on a web App project and I have the following component that is returned by antd Menu object.
const items = [
{
label: <Link to='/register'>Register</Link>,
key: 'register',
icon: <UserAddOutlined />,
style: { marginLeft: 1030}, // problem: hard-coded margin
},
{
label: <Link to='/login'>Login</Link>,
key: 'login',
icon: <UserOutlined />,
style: { marginLeft: 'auto'},
},
];
return <Menu mode="horizontal" items={items} />;
Now I have an object named user. If user is not null (which means there is a user who is logged in currently), I want to hide register in the above items object; otherwise I want to show register in the Menu. The Menu component will be looked like:
Can anyone help me with that?
2 Respuestas
Responde la pregunta0
You can insert this code after declaring items,
if(users!==null)
{
items.splice(0,1) //removes first array element which is the register button
}
I would highly recommend you to use state for this purpose because that is the intended way for such cases.
By that I mean encapsulate the items object into a state and use the code above during every re-render using something like useeffect hook
Look at the question and the verified answer below to understand how to do it in newer versions of react
how to update an object using useEffect in Reactjs and Typescript
0
You just have to remember that items is a regular array. Not everything in React are exotic objects. A lot of your code will be using normal objects like strings, arrays, numbers etc. Don't be blinded by the array literal syntax that you forget that it's just an array.
There is already an answer showing what you can do to the items array to remove the first item. But you can also just write it simply:
let items = [];
if (user !== null) {
items.push({
label: <Link to='/register'>Register</Link>,
key: 'register',
icon: <UserAddOutlined />,
style: { marginLeft: 1030}, // problem: hard-coded margin
})
}
items.push({
label: <Link to='/login'>Login</Link>,
key: 'login',
icon: <UserOutlined />,
style: { marginLeft: 'auto'},
})
return <Menu mode="horizontal" items={items} />;