How to retrieve data from a specific getters in vue?
this.$store.getters('client/list'))
TypeError: _this.$store.getters is not a function
at eval (Login2.vue?3936:64)
Step 1: Set the getter in the store.
getters: {
clientList: state => {
return state.clientList
}
}
Step 2: Call the getter in your component as computed
computed: {
clientList () {
return this.$store.getters.clientList
}
}
Check your syntax. The getter you posted won't work because you're missing the module-specific syntax.
As an example from the following link:
this.$store.getters['ModuleA/getCategory'](this.index)
See more here: Vue.js 2/Vuex - How to call getters from modules that has attribute namespaced:true without mapGetters?
Related
My computed property receives information from a store action (with an axios call in it) when component mounts initially. However I need to change its value directly later on:
myComputedProperty: {
get: function () {
return this.myStoreActionResult;
},
set: function (newValue) {
return newValue
}
}
With this setup however, I can't change its value:
console.log(this.myComputedProperty)
this.myComputedProperty = 'new value!'
console.log(this.myComputedProperty)
I expected this to display the initial value (based on store information) and then the new value. Instead, it displays twice the initial value: I can't change the computed property's value directly.
Is there a way to achieve that, and if so how?
Computed properties are used for returning a calculated (and cached) value, so you cannot directly set value of it because it doesn't exists at all. Behind computed property are variables that you can set with setter, like in your example. All you need is set new value of referencing variable:
myComputedProperty: {
get: function () {
return this.myStoreActionResult;
},
set: function (newValue) {
this.myStoreActionResult = newValue;
return newValue
}
}
Using computed variable like in example above is useless, because you indirectly modify original property.
Yes, it's possible.
Refer to Vue.js documentation here: Computed Setter
Your code would become something like this:
myComputedProperty: {
get: function () {
return this.myStoreActionResult;
},
set: function (newValue) {
this.myStoreActionResult = newVaue;
}
}
When I'm trying to use Template strings inside the data function in vuejs but, it always returns undefined any idea how to solve this ?
I was trying to make a URL for an API call dynamic
Cheers,
data() {
return {
baseUrl: `https://example.com/api/json?key=${this.key}`,
key: "IzNDU2Nzg5MDEyMzQ1Njc"
};
}
This is a JavaScript issue. If you run the following simple example in JavaScript you'll get a "is not defined" error (when running in strict mode).
{ a: `${b}`, b: "123" }
> VM246:1 Uncaught ReferenceError: b is not defined
You can't reference an adjacent variable ('key' in your example) in an object literal declaration.
You can use a Vue.je computed property for baseURL:
computed: {
baseUrl() {
return `https://example.com/api/json?key=${this.key}`;
}
}
The data property cannot be made dynamic. Use a computed property like below:
computed: {
baseUrl() {
return `https://example.com/api/json?key=${this.key}`
}
}
I am trying to separate out some code that is common among many calls in my Vuex mutations. I am getting the feeling that this is discouraged but I don't understand why.
Have a look at an image of some sample code below:
I have added this 'helpers' entry in the Vuex - this obviously doesn't exist but how can I call the shared helper function 'getColumn' from mutations and/or actions?
Or do I have resort to calling a static method on a 'VuexHelper' class? :(
Something like:
Note
I have already looked at the following:
Vue Mixins - yes, something like that could work but is not
supported in Vuex - also, vue methods don't return a value...
I have looked at Modules but these still don't give me what I need, i.e. a simple re-usable function that returns a value.
Thanks
I don't see why you may want to put the helper function within the store. You can just use a plain function.
function getColumn(state, colName) {
// Do your thing.
}
const vstore = new Vuex.Store({
// ....
mutations: {
removeColumn(state, colName) {
var column = getColumns(state, colName);
}
}
};
On the other hand, if you really need that, you can access the raw module and all that's included:
var column = this._modules.root._rawModule.helpers.getColumns(state, colName);
Although this syntax is not documented and can change for later versions.
You can implement your Vuex getter as a method-style getter. This lets you pass in the specific column as an argument:
getters: {
getColumn: state => colName => {
return state.columns[colName] || null
}
}
Then getColumn can be used within the store like so:
let column = getters.getColumn('colNameString')
vuex docs > getters > method style access
Within a Vuex store mutation, is it possible to access a getter? Consider the below example.
new Vuex.Store({
state: {
question: 'Is it possible to access getters within a Vuex mutation?'
},
mutations: {
askQuestion(state) {
// TODO: Get question from getter here
let question = '';
if (question) {
// ...
}
}
},
getters: {
getQuestion: (state) => {
return state.question;
}
}
});
Of course the example doesn't make much sense, because I could just access the question property directly on the state object within the mutation, but I hope you see what I am trying to do. That is, conditionally manipulating state.
Within the mutation, this is undefined and the state parameter gives access to the state object, and not the rest of the store.
The documentation on mutations doesn't mention anything about doing this.
My guess would be that it's not possible, unless I missed something? I guess the alternative would be to either perform this logic outside of the store (resulting in code duplication) or implementing an action that does this, because actions have access to the entire store context. I'm pretty sure that it's a better approach, that is to keep the mutation focused on what it's actually supposed to do; mutate the state. That's probably what I'll end up doing, but I'm just curious if accessing a getter within a mutation is even possible?
Vuex store mutation methods do not provide direct access to getters.
This is probably bad practice*, but you could pass a reference to getters when committing a mutation like so:
actions: {
fooAction({commit, getters}, data) {
commit('FOO_MUTATION', {data, getters})
}
},
mutations: {
FOO_MUTATION(state, {data, getters}) {
console.log(getters);
}
}
* It is best practice to keep mutations a simple as possible, only directly affecting the Vuex state. This makes it easier to reason about state changes without having to think about any side effects. Now, if you follow best practices for vuex getters, they should not have any side effects in the first place. But, any logic that needs to reference getters can run in an action, which has read access to getters and state. Then the output of that logic can be passed to the mutation. So, you can pass the reference to the getters object to the mutation, but there's no need to and it muddies the waters.
If you put your getters and mutations in separate modules you can import the getters in the mutations and then do this:
import getters from './getters'
askQuestion(state) {
const question = getters.getQuestion(state)
// etc
}
If anyone is looking for a simple solution, #bbugh wrote out a way to work around this here by just having both the mutations and getters use the same function:
function is_product_in_cart (state, product) {
return state.cart.products.indexOf(product) > -1
}
export default {
mutations: {
add_product_to_cart: function (state, product) {
if (is_product_in_cart(state, product)) {
return
}
state.cart.products.push(product)
}
},
getters: {
is_product_in_cart: (state) => (product) => is_product_in_cart(state, product)
}
}
You also can reference the Store object within a mutation, if you declare the store as an expression, like this:
const Store = new Vuex.Store({
state: {...},
getters: {...},
mutations: {
myMutation(state, payload) {
//use the getter
Store.getters.getter
}
}
});
Vuex 4
const state = () => ({
some_state: 1
})
const getters = {
some_getter: state => state.some_state + 1
}
const mutations = {
GET_GETTER(state){
return getters.some_getter(state)
}
}
Somewhere in you component
store.commit('GET_GETTER') // output: 2
Another solution is to import the existing store. Assuming you're using modules and your module is called foo, your mutator file would look like this store/foo/mutations.js:
import index from '../index'
export const askQuestion = (state, obj) => {
let store = index()
let getQuestion = store.getters['foo/getQuestion']
}
I'm not saying this is best practise but it seems to work.
At least in Vuex 3/4, I've reached for this pattern numerous times: simply use this.getters.
Inside a mutation, regardless if you are inside a Vuex module or not, this is always reference to your root store.
So:
mutations: {
doSomething(state, payload) {
if (this.getters.someGetter) // `this.getters` will access you root store getters
}
Just to be extra clear, this will work if the getter you're trying to access belongs to your root store OR to any other non-namespaced module, since they are all added (flattened) to this.getters.
If you need access to a getter that belongs to any namespaced Vuex module, just remember they are all added to the root store getters as well, you just have to use the correct key to get to them:
this.getters['MyModuleName/nameOfGetter']
The great thing about this is that it also allows you to invoke mutations that belong either to the root store or any other store. this.commit will work exactly as expected as well Source
I'm trying to create an object in one part of vuex store, and then pass id to it to another object, and i'm not sure how to properly do that since mutations can't return returning anything (in this case, id).
Two store objects look like this:
// store/report.js
const state = {
name: 'Untitled Report',
subReportIds: []
};
// store/subReport.js
const state = { ... }
And i'd like this action to create blank report, then blank subreport, and then assign subreport id to newly created report. (subreports are independent entities, and can be used by multiple reports, hence different area in store)
const actions = {
createNewReport({ state, commit }) {
commit(mutationTypes.CREATE_NEW_REPORT)
// below doesn't work - i can't get return from mutation
let newSubreportId = commit(mutationTypes.ADD_NEW_SUBREPORT)
// if this worked, i'd then do something like
commit(mutationTypes.ADD_SUBREPORT_TO_REPORT, newSubreportId)
}
};
How can i achieve the above?
So best way to accomplish to me would be to dispatch actions instead of committing the mutations. If you look at the methods in Vuex source, commit only executes with no return (so is a void) and dispatch returns the value you return from the action (which is a function)
For my actions, i always return a promise so that i can compose them like you mention above. Here is an example.
fetchSomething ({ commit }) {
return mockApiGetIds()
.then(response => {
commit({
type: SOME_MUTATION,
ids: response
});
return response;
});
},
Disclaimer : I don't know if it is truely a good idea, but at least, it seems to work, and to me, it feels prettier than having to use actions and promises, or to generate the id in the action...
With your mutation, you can pass an argument. To return a value from a mutation (like a newly created id), I write it to a placeholder in that argument :
someMutation(state, arg){
//...
arg.out = {
status : "succeed"
}
}
//...
this.$store.commit('someMutation', arg);
if(arg.out !== "succeed") console.log("ERROR");