I am trying to update a single property of an object from an array using vuex.
here is my code in store file.
export default{
namespaced: true,
state: {
customers: null,
},
mutations: {
UPDATE_MODIFIED_STATE(state, value) {
state.customers = [
...state.customers.filter(item => item.Id !== value.Id),
value,
];
},
},
And below code is from my .vue file.
export default {
computed: {
customerArray() {
return this.$store.state.CustomerStore.customers;
},
},
methods: {
...mapMutations('CustomerStore', ['UPDATE_MODIFIED_STATE']),
updateCustomers() {
if(someCondition) {
this.customerArray.forEach((element) => {
element.IsModified = true;
this.UPDATE_MODIFIED_STATE(element);
});
}
/// Some other code here
},
},
};
As you can see I want to update IsModified property of object.
It is working perfectly fine. it is updating the each customer object.
Just want to make sure, is it correct way to update array object or I should use Vue.set.
If yes, I should use Vue.set, then How can I use it here.
You are actually not mutating your array, what you do is replacing the original array with a new array generated by the filter function and the passed value. So in your example there is no need to use Vue.set.
You can find more information about replacing an array in the vue documentation.
The caveats begin however when you directly set an item with the index or when you modify the length of the array. When doing this the data will no longer be reactive, you can read more about this here.
For example, consider the following inside a mutation:
// If you update an array item like this it will no longer be reactive.
state.customers[0] = { Id: 0, IsModified: true }
// If you update an array item like this it will remain reactive.
Vue.set(state.customers, 0, { Id: 0, IsModified: true })
Related
Context:
I have a reports application that contains a report editor. This Report Editor is used to edit the contents of the report, such as the title, the criteria for filtering the results, the time range of results, etc..
The Problem:
There is something wrong with the way I have used Vuex/Vuejs in my components I believe. My store contains getters for each aspect of this report editor. Like this:
const getters = {
activeReportTitle: state => {
return state.activeReport.title;
},
activeReportID: state => {
return state.activeReport.id;
},
timeframe: state => {
return state.activeReport.timeframe;
},
includePreviousData: state => {
return state.activeReport.includePreviousData;
},
reportCriteria: state => {
return state.activeReport.reportCriteria;
},
emailableList: state => {
return state.activeReport.emailableList;
},
dataPoints: state => {
return state.activeReport.configuration?.dataPoints;
},
...
Each getter is used in a separate component. This component uses the getter only to initialize the local data, and uses actions to modify the state. The way I have done this is by adding a local data property and a watcher on the getter that changes the local data property. The component is using the local data property and that data property is sent to the action and the getter is updated.
ReportSearchCriteria.vue
...
data() {
return {
localReportCriteria: [],
currentCriteria: "",
};
},
watch: {
reportCriteria: {
immediate: true,
handler(val) {
this.localReportCriteria = [...val];
}
}
},
computed:{
...reportStore.mapGetters(['reportCriteria'])
},
methods: {
...reportStore.mapActions(["updateReportCriteria"]),
addSearchCriteria() {
if (this.currentCriteria) {
this.localReportCriteria.push(this.currentCriteria);
this.updateReportCqriteria(this.localReportCriteria);
}
this.currentCriteria = "";
this.$refs['reportCriteriaField'].reset();
},
...
The hierarchy of the components is set up like this
Reports.Vue
GraphEditor.vue
ReportSearchCriteria.vue
Could you clarify what the problem is? Does the 'reportCriteria' not get updated when it's supposed to? How does the function 'updatedReportCriteria' look like? You use mutations to update a state in the store. Also, you have a typo when you're calling the action.
I have a computed variable getting a value from the VUEX store. I only want to get this value once, and then save it locally into a variable so I can edit the said variable without doing any mutations on my store value. How can this be done?
Any help will be really appreciated.
What you can do is create a computed property with a get and set method:
data() {
return {
myValueCopy: null
}
},
computed: {
myValue: {
get() {
if (this.myValueCopy === null) {
return this.$store.getters.myValue;
}
return this.myValueCopy;
},
set(value) {
this.myValueCopy = value;
}
}
}
If there's no local copy of the data return the store value, else return the copy. When setting the data, update the local copy not the store.
I ended up using something similar to the other answer:
data() {
return {
LocalText: { type: String },
}
},
computed: {
...mapGetters('store', ['storevar']),
currentText: function () {
return this.storevar
},
},
created() {
this.LocalText= this.currentText
}
What I have done here is that I first made a new variable for the text to be locally stored - LocalText. I have also added a getter that gets the store variable from the store and a computed function that returns the value of the storevar. Finally, I have assigned the value of the storevar to my LocalText when the page is first created using the created() function.
I have this object of arrays that I'm tryin to watch every update of.
myData = {
"299":[527],
"376":[630,629]
}
I read this documentation on watching an object which instructed to use either this.$set(object, propertyName, value) or Object.assign({}, this.object, dataToBeAppended) to watch an object. I used this.$set.
export default {
...
data() {
return {
myData: {},
};
},
watch: {
myData(newVal) {
console.log(`🔴localStorage`);
},
},
methods: {
onFoldChange(propertyName) {
const newArr = [...]
this.$set(this.myData, propertyName, newArr);
},
}
}
Unlike what I expected, vue captures changes on property only. Changes in value to an existing property are not being watched. For example, if a property "299" was newly added, it will print 🔴localStorage. When the value of a property "299" is updated from [527] to something else, nothing is fired. When I print myData, I see every value updated correctly. It is just that watch isn't capturing the changes.
The documentation also described we can watch an array using this.$set(this.myData, indexOfItem, newValue) so I also tried array version of the above code, like this.
this.$set(this.myData[propertyName], index, newValueToAdd);
This time it doesn't listen at all. Not even the first entry.
Is there any better way to solve this issue? How do others watch an object? Is the complication coming from the type of values (array) ?
Currently, myData watcher observes only an object. Object contains pointers to arrays as in JS Objects & Arrays are passed by reference not by copy. That's why it can detect only changes in keys and with simple values. If you want to observe it deeper - I mean also those subarrays (or subobjects) - just use deep watch.
watch: {
myData: {
deep: true,
handler (newVal) {
console.log(`🔴localStorage`);
}
}
}
Another possible solution could be to use some Array.prototype operation to modify an array if it already exists. E.g:
methods: {
onFoldChange(propertyName) {
if (propertyName in this.myData && Array.isArray(this.myData[propertyName])) {
this.myData[properyName].push(162) // Some random value
} else {
const newArr = [...]
this.$set(this.myData, propertyName, newArr);
}
},
}
please help with .$set data on vue , after read docs of vuejs.org I did not realize what must be index in $set when my data is already null and also syntax I need to write. please provide the syntax need for set data in this specific example. thank you.
//in vue js components:
data() {
return {
columnDefs: null
};
computed: {
onLoadColumns() {
// some logic here (manipulate received props from parent)
// logic bring this [{},{},{}]
// sth = [{},{},{}]
// now want to .$set() , (or maybe $add()) that array to data obj for reactivity.
// what syntax look like? this below didn't work.
this.$set(this.columnsDef, 0, sth);
}
You have a typo: should be this.$set(this.columnDef, 0, sth);. Not this.columnsDef - without s.
Also try to init you columnDef with [] in data:
data() {
return {
columnDefs: []
}
},
Or set empty array right before assigning to zero index:
this.columnDef = []
this.$set(this.columnDef, 0, sth)
I had an API call to the backend and based on the returned data, I set the reactive data dynamically:
let data = {
quantity: [],
tickets: []
}
api.default.fetch()
.then(function (tickets) {
data.tickets = tickets
tickets.forEach(ticket => {
data.quantity[ticket.id] = 0
})
})
Based on this flow, how can I set watcher for all reactive elements in quantity array dynamically as well?
You can create a computed property, where you can stringify the quantity array, and then set a watcher on this computed property. Code will look something like following:
computed: {
quantityString: function () {
return JSON.stringify(this.quantity)
}
}
watch: {
// whenever question changes, this function will run
quantityString: function (newQuantity) {
var newQuantity = JSON.parse(newQuantity)
//Your relevant code
}
}
Using the [] operator to change a value in an array won't let vue detect the change, use splice instead.