I am trying to pass a variable as the param to vue-router so it can be set dynamically. Pretty much as the example below:
<router-link :to="{
name: notification.name,
(notification.param_name): notification.param_value
}">Blabla</router-link>
I am not looking at setting the key like this: var[notification.param_name].
I suppose this question could be expanded to a more general problem, but I am having a hard time explaining it in another way.
It'd be simplest to make it a computed which returns the definition of the route based on the notification object (note that you need to specify the params inside the params property of the object):
computed: {
notificationRoute() {
let { name, param_name, param_value } = this.notification;
return { name, params: { [param_name]: param_value } };
}
}
And bind that to the to:
<router-link :to="notificationRoute">Blabla</router-link>
Related
I'm working on a vue cli project where items have two state equipped and unequipped.
This State is controlled by a Boolean located in the Props. Since you can switch the state I had to create a data isEquipped set to false by default.
I then added a watcher but it doesn't change my data value if my props is set to True.
Here's the code
name: "Item",
props: {
Index : Number,
name: String,
desc : String,
bonus: Array,
equipped : Boolean
},
data() {
return {
isEquipped : false
}
},
watch: {
equipped: function(stateEquipped) {
this.isEquipped = stateEquipped;
},
},
So for instance let's say I created a new item with equipped set to True, the watcher doesn't trigger and isEquipped stays at False, is there any reason to that ?
I came across multiple similar questions like this one Vue #Watch not triggering on a boolean change but none of them helped me
If you want to use watch then you can try define it as:
equipped: {
handler () {
this.isEquipped = !this.isEquipped;
},
immediate: true
}
This will change the value of this.isEquipped whenever the value of equipped will change.
I am not sure what is the use case of isEquipped but seeing your code you can use the props directly unless there is a situation where you want to mutate the isEquipped that is not related to the props.
Why not just use a computed value instead?
{
// ...
computed: {
isEquipped () {
// loaded from the component's props
return this.equipped
}
}
}
You can then use isEquipped in your components just as if it was defined in your data() method. You could also just use equipped in your components directly as you don't transform it in any way.
<p>Am I equipped? - <b>{{ equipped }}</b></p>
Watchers are "slow" and they operate on vue's next life-cycle tick which can result in hard to debug reactivity problems.
There are cases where you need them, but if you find any other solution, that uses vue's reactivity system, you should consider using that one instead.
The solution using a computed value from #chvolkmann probably also works for you.
There is a imho better way to do this:
export default {
name: "Item",
props: {
Index : Number,
name: String,
desc : String,
bonus: Array,
equipped : Boolean
},
data() {
return {
isEquipped : false
}
},
updated () {
if (this.equipped !== this.isEquipped) {
this.isEquipped = this.equipped
// trigger "onEquip" event or whatever
}
}
}
The updated life-cycle hook is called -as the name suggests- when a component is updated.
You compare the (unchanged) isEquipped with the new equipped prop value and if they differ, you know that there was a change.
I have state:
{
studentId: 1,
studentName: "Student",
religion: {
religionId: 1,
religionName: "RELIGION"
}
}
How to access religionName in react?
I have tried access my student state like this:
const {studentState} = useContext(StudentContext);
return (
<div>
{studentState.studentId}
{studentState.studentName}
{studentState.religion.religionName}
</div>
);
Undifined result when using {studentState.religion.religionName}
Although it is hard to tell without a minimal reproducible example, one thing that stands out is the use of the curly braces around {studentState}.
If the object in the example you provided is the entire context value, you should not use curly braces, because this would try to extract a property called studentState from the context object, which does not exist in your example. Instead, you just want the entire context value:
const studentState = useContext(StudentContext);
This assumes you have previously created your StudentContext object somewhere and provided a value, something like this:
const StudentContext = React.createContext(null);
// Later, define a value
const studentState = {
studentId: 1,
studentName: "Student",
religion: {
religionId: 1,
religionName: "RELIGION"
}
};
// Then in a component, render the context provider:
<StudentContext.Provider value={studentState}>
...
</StudentContext.Provider>
Read up on object destructuring in JavaScript (this is a good intro). That is what the curly braces you are using are doing.
You must use condition for handling this situation..
Try this one
{ studentState.religion && studentState.religion.religionName}
I want to create rootStore which contains others store. The problem is that the children contain properties like:
id: types.identifier(types.string),
And when I create the rootStore, I get an error from the child:
[mobx-state-tree] Error while converting {} to SomeModelStore: at path "/id" value undefined is not assignable to type: identifier(string) (Value is not a string), expected an instance of identifier(string) or a snapshot like identifier(string) instead.
I tried to use types.late but it did not help.
The solution I found is to wrap all properties into types.maybe
Examples:
error:
https://codesandbox.io/s/yvnznxyvyj?module=%2Fmodels%2FSomeModelStore.js
workaround:
https://codesandbox.io/s/0mv558yq50?module=%2Fmodels%2FSomeModelStore.js
Here https://codesandbox.io/s/yvnznxyvyj?module=%2Fmodels%2FSomeModelStore.js you create an empty object
.model("FirstStore", {
item: types.optional(SomeModelStore, {})
})
but type
SomeModelStore
didn't support empty fields. If you write like this
export const FirstStore = types
.model("FirstStore", {
item: types.optional(SomeModelStore, {
id: 'defaultId',
activate: false,
name: 'defaultName'
})
})
it will work. Or you can use "types.maybe" instead of "types.optional".
export const FirstStore = types
.model("FirstStore", {item: types.maybe(SomeModelStore)})
Also read about types.reference
I think it's a better way to use it in your case.
In a Vue Js component, I need to loop through an object on the mounted hook that's in local storage in Vuex to update the data properties as you can see in code example.
I'm trying to update this.title, this.body, this.id whereby the rightHere variable in the loop is outputting these names as string values as the var you can see.
this.rightHere
...is the problem I know, and is obviously trying to target a data property "rightHere" which doesn't exist. But I don't know how else to overcome this in javascript and make rightHere output the string as needed? So how do I use this in a loop to dynamically change but tell Vue to update this. on each iteration?
data() {
return {
title: '',
body: '',
id: '',
}
},
mounted() {
for (var rightHere in this.$store.getters.getObject) {
if (this.$store.getters.getObject.hasOwnProperty(rightHere )) {
this.rightHere = this.$store.getters.getObject[rightHere ]
}
}
},
You would typically set the key in your template. It's a reserved word.
<div v-for='item in items' :key='$store.getters.getKey(item)'>{{item.title}}</div>
I am using firebase, and angularfire.
there are so many ways to do CRUD with the Firebase Api
actually, I still don't get what is specific difference for using
$add with $firebaseArray
.push() method
.set() method
I think they are technically same, I prefer to use .set method() without knowing the exact reason, why I'd using that. is there any specific reason to not use it? what is exactly $firebaseArray did? if we could just declare basic reference variable.
in this case:
var usersRef = Ref.child('users');
$scope.createUser = function() {
$scope.userRef.child($id).set({
name: name
});
};
or
$scope.data = $firebaseArray(Ref.child('users'));
$scope.createUser = function() {
$scope.data.child($id).$add({
name: name
});
};
thank you.
If I have the following data tree in Firebase:
{
users:
{
key: { name:"bob" }
}
}
When I do an $add, I will create a new item in the tree
$scope.data.child('users').$add({
name: name
});
Since $add uses the Push method in Firebase, new random Key will be used when pushing data to the child.
{
users:
{[
key: { name:"bob" },
key2: { name:"name" }
]}
}
If I do a set on the same Users object, I will overwrite the data that is already there. So, in your example, without specifying a key, you will overwrite the entire user object.
$scope.userRef.child('users').set({
name: name
});
};
This will result with this data
{
users:
{
name: "name"
}
}
This happens because any null values you pass to the Set method will delete any data that was originally there.
Passing null to set() will remove the data at the specified location.
https://www.firebase.com/docs/web/api/firebase/set.html