Related
Why do I get this error:
Error [vuex] Do not mutate vuex store state outside mutation handlers.
What does it mean?
It happens when I try to type in the edit input file.
pages/todos/index.vue
<template>
<ul>
<li v-for="todo in todos">
<input type="checkbox" :checked="todo.done" v-on:change="toggle(todo)">
<span :class="{ done: todo.done }">{{ todo.text }}</span>
<button class="destroy" v-on:click="remove(todo)">delete</button>
<input class="edit" type="text" v-model="todo.text" v-todo-focus="todo == editedTodo" #blur="doneEdit(todo)" #keyup.enter="doneEdit(todo)" #keyup.esc="cancelEdit(todo)">
</li>
<li><input placeholder="What needs to be done?" autofocus v-model="todo" v-on:keyup.enter="add"></li>
</ul>
</template>
<script>
import { mapMutations } from 'vuex'
export default {
data () {
return {
todo: '',
editedTodo: null
}
},
head () {
return {
title: this.$route.params.slug || 'all',
titleTemplate: 'Nuxt TodoMVC : %s todos'
}
},
fetch ({ store }) {
store.commit('todos/add', 'Hello World')
},
computed: {
todos () {
// console.log(this)
return this.$store.state.todos.list
}
},
methods: {
add (e) {
var value = this.todo && this.todo.trim()
if (value) {
this.$store.commit('todos/add', value)
this.todo = ''
}
},
toggle (todo) {
this.$store.commit('todos/toggle', todo)
},
remove (todo) {
this.$store.commit('todos/remove', todo)
},
doneEdit (todo) {
this.editedTodo = null
todo.text = todo.text.trim()
if (!todo.text) {
this.$store.commit('todos/remove', todo)
}
},
cancelEdit (todo) {
this.editedTodo = null
todo.text = this.beforeEditCache
},
},
directives: {
'todo-focus' (el, binding) {
if (binding.value) {
el.focus()
}
}
},
}
</script>
<style>
.done {
text-decoration: line-through;
}
</style>
stores/todos.js
export const state = () => ({
list: []
})
export const mutations = {
add (state, text) {
state.list.push({
text: text,
done: false
})
},
remove (state, todo) {
state.list.splice(state.list.indexOf(todo), 1)
},
toggle (state, todo) {
todo.done = !todo.done
}
}
Any ideas how I can fix this?
It could be a bit tricky to use v-model on a piece of state that belongs to Vuex.
and you have used v-model on todo.text here:
<input class="edit" type="text" v-model="todo.text" v-todo-focus="todo == editedTodo" #blur="doneEdit(todo)" #keyup.enter="doneEdit(todo)" #keyup.esc="cancelEdit(todo)">
use :value to read value and v-on:input or v-on:change to execute a method that perform the mutation inside an explicit Vuex mutation handler
This issue is handled here: https://vuex.vuejs.org/en/forms.html
Hello I have get the same problem and solve it with clone my object using one of the following:
{ ...obj} //spread syntax
Object.assign({}, obj)
JSON.parse(JSON.stringify(obj))
For your code I think you need to replace this part
computed: {
todos () {
// console.log(this)
return this.$store.state.todos.list
}
}
With this
computed: {
todos () {
// console.log(this)
return {...this.$store.state.todos.list}
}
}
I don't make sure if this is the best way but hope this helpful for other people that have the same issue.
This error may come from the fact you shallow cloned an object.
Meaning that you've tried to copy an object but an object is not a primitive type (like String or Number), hence it's passed by reference and not value.
Here you think that you cloned one object into the other, while you are still referencing the older one. Since you're mutating the older one, you got this nice warning.
Here is a GIF from Vue3's documentation (still relevant in our case).
On the left, it's showing an object (mug) being not properly cloned >> passed by reference.
On the right, it's properly cloned >> passed by value. Mutating this one does not mutate the original
The proper way to manage this error is to use lodash, this is how to load it efficiently in Nuxt:
Install lodash-es, eg: yarn add lodash-es, this is an optimized tree-shakable lodash ES module
you may also need to transpile it in your nuxt.config.js with the following
build: {
transpile: ['lodash-es'],
}
load it into your .vue components like this
<script>
import { cloneDeep } from 'lodash-es'
...
const properlyClonedObject = cloneDeep(myDeeplyNestedObject)
...
</script>
Few keys points:
lodash is recommended over JSON.parse(JSON.stringify(object)) because it does handle some edge-cases
we only load small functions from lodash and not the whole library thanks to this setup, so there is no penalty in terms of performance
lodash has a lot of well battle-tested useful functions, which is heavily lacking in JS (no core library)
UPDATE: structuredClone is also native and quite performant if you're looking for a solution for a deep copy, bypassing the need for Lodash at all.
There is no headache if you can use lodash
computed: {
...mapState({
todo: (state) => _.cloneDeep(state.todo)
})
}
Just in case someone's still being troubled by this,
I got my code working by making a duplicate/clone of the store state.
In your case, try something like this...
computed: {
todos () {
return [ ...this.$store.state.todos.list ]
}
}
It's basically a spread operator which results in making a clone of the todos.list array. With that, you're not directly changing the values of your state, just don't forget commit so your mutations will be saved in the store.
export default new Vuex.Store({
...
strict: true
})
try to comment "strict"
If you are using Vuex Modules, you might bump into this error if your module's data property is an object, instead of a function that returns an object, and you are sharing this Module between more than one Store.
So instead of:
// In stores/YourModule.js
export default {
state: { name: 'Foo' },
}
Change it to:
// In stores/YourModule.js
export default {
state: () => {
return { name: 'Foo' };
},
}
This is actually documented here:
Sometimes we may need to create multiple instances of a module, for
example:
Creating multiple stores that use the same module (e.g. To avoid
stateful singletons in the SSR (opens new window)when the
runInNewContext option is false or 'once'); Register the same module
multiple times in the same store. If we use a plain object to declare
the state of the module, then that state object will be shared by
reference and cause cross store/module state pollution when it's
mutated.
This is actually the exact same problem with data inside Vue
components. So the solution is also the same - use a function for
declaring module state (supported in 2.3.0+):
If your data is an array with objects inside. Below snippet is the solution
const toyData = await this.$store.dispatch(
`user/fetchCoinToys`,
payload
)
const msgList = toyData.msglist.map((data) => {
return { ...data }
})
I had to add mutation and call it instead of setting directly.
wrong:
someAction({state, rootState}) {
state.someValue = true;
}
right:
mutations: {
...
setSomeValue(state, val) {
state.someValue = val;
},
...
}
...
someAction({state, commit, rootState}) {
commit('setSomeValue', true);
}
It is not your case but if someone is using typescript and is having the same problem, adding this: any as the first param in your method or somewhere else should fix the problem
I was wondering if there is a way of creating computed props programatically, while still accessing the instance to achieve dynamic values
Something like that (this being undefined below)
<script>
export default {
computed: {
...createDynamicPropsWithTheContext(this), // helper function that returns an object
}
}
</script>
On this question, there is a solution given by Linus: https://forum.vuejs.org/t/generating-computed-properties-on-the-fly/14833/4 looking like
computed: {
...mapPropsModels(['cool', 'but', 'static'])
}
This works fine but the main issue is that it's fully static. Is there a way to access the Vue instance to reach upon props for example?
More context
For testing purposes, my helper function is as simple as
export const createDynamicPropsWithTheContext = (listToConvert) => {
return listToConvert?.reduce((acc, curr) => {
acc[curr] = curr
return acc
}, {})
}
What I actually wish to pass down to this helper function (via this) are props that are matching a specific prefix aka starting with any of those is|can|has|show (I'm using a regex), that I do have access via this.$options.props in a classic parent/child state transfer.
The final idea of my question is mainly to avoid manually writing all the props manually like ...createDynamicPropsWithTheContext(['canSubmit', 'showModal', 'isClosed']) but have them populated programatically (this pattern will be required in a lot of components).
The props are passed like this
<my-component can-submit="false" show-modal="true" />
PS: it's can-submit and not :can-submit on purpose (while still being hacked into a falsy result right now!).
It's for the ease of use for the end user that will not need to remember to prefix with :, yeah I know...a lot of difficulty just for a semi-colon that could follow Vue's conventions.
You could use the setup() hook, which receives props as its first argument. Pass the props argument to createDynamicPropsWithTheContext, and spread the result in setup()'s return (like you had done previously in the computed option):
import { createDynamicPropsWithTheContext } from './props-utils'
export default {
⋮
setup(props) {
return {
...createDynamicPropsWithTheContext(props),
}
}
}
demo
If the whole thing is for avoiding using a :, then you might want to consider using a simple object (or array of objects) as data source. You could just iterate over a list and bind the data to the components generated. In this scenario the only : used are in the objects
const comps = [{
"can-submit": false,
"show-modal": true,
"something-else": false,
},
{
"can-submit": true,
"show-modal": true,
"something-else": false,
},
{
"can-submit": false,
"show-modal": true,
"something-else": true,
},
]
const CustomComponent = {
setup(props, { attrs }) {
return {
attrs
}
},
template: `
<div
v-bind="attrs"
>{{ attrs }}</div>
`
}
const vm = Vue.createApp({
setup() {
return {
comps
}
},
template: `
<custom-component
v-for="(item, i) in comps"
v-bind="item"
></custom-component>
`
})
vm.component('CustomComponent', CustomComponent)
vm.mount('#app')
<script src="https://unpkg.com/vue#3"></script>
<div id="app">{{ message }}</div>
Thanks to Vue's Discord Cathrine and skirtle folks, I achieved to get it working!
Here is the thread and here is the SFC example that helped me, especially this code
created () {
const magicIsShown = computed(() => this.isShown === true || this.isShown === 'true')
Object.defineProperty(this, 'magicIsShown', {
get () {
return magicIsShown.value
}
})
}
Using Object.defineProperty(this... is helping keeping the whole state reactive and the computed(() => can reference some other prop (which I am looking at in my case).
Using a JS object could be doable but I have to have it done from the template (it's a lower barrier to entry).
Still, here is the solution I came up with as a global mixin imported in every component.
// helper functions
const proceedIfStringlean = (propName) => /^(is|can|has|show)+.*/.test(propName)
const stringleanCase = (string) => 'stringlean' + string[0].toUpperCase() + string.slice(1)
const computeStringlean = (value) => {
if (typeof value == 'string') {
return value == 'true'
}
return value
}
// the actual mixin
const generateStringleans = {
created() {
for (const [key, _value] of Object.entries(this.$props)) {
if (proceedIfStringlean(key)) {
const stringleanComputed = computed(() => this[key])
Object.defineProperty(this, stringleanCase(key), {
get() {
return computeStringlean(stringleanComputed.value)
},
// do not write any `set()` here because this is just an overlay
})
}
}
},
}
This will scan every .vue component, get the passed props and if those are prefixed with either is|can|has|show, will create a duplicated counter-part with a prefix of stringlean + pass the initial prop into a method (computeStringlean in my case).
Works great, there is no devtools support as expected since we're wiring it directly in vanilla JS.
This must have been asked before, but I failed to find such question, so let me apologize in advance if there is one.
In my Vue component (written using vue-property-decorator in a class-based manner) I have a data property which is an object:
const emptyFilters = {
name: ''
};
export default class MyComponent extends Vue {
filtersFields = emptyFilters;
...
}
At some point I'd like to clean the filters. As for now there's only one filter, so I can do this:
this.filtersFields.name = '';
but to make this work with any number of filters, I'd like to do something like this:
this.filtersFields = emptyFilters;
The method above fails which is presumably because I set the property that is an observable to a new object hence the subscription of the model keeps observing the old object instead the new one. As far as I understand, Vue.set is what I need to use to set the whole this.filtersFields to a new object (emptyFilters). I tried:
this.$set(this, 'filtersFields', emptyFilters);
but this fails too (an input with v-model="filtersFields.name" is not cleared). What am I doing wrong? How to use Vue.set correctly? Is it only used only for adding a new property which was not set before? Do I need to use some other method?
PS As a solution based on answers below, I decided not to recreate the object from itself, but use a "factory" getter:
// instead of using a const emptyFilters we use a getter because otherwise
// emptyFilters becomes an observable and should be recreated each time anyway
const getEmptyFilters = (): examinationsFilters => ({
name: ''
});
...
// (initializing)
filtersFields: examinationsFilters = getEmptyFilters();
...
// (in method)
this.filtersFields = getEmptyFilters();
As Jesus Galvan correctly points out, this is very likely caused by your initialization code. Let's say you have the following template:
<template>
<div>
<input v-model="filtersFields.firstName" type="text" />
<input v-model="filtersFields.lastName" type="text" />
<button #click="onReset">reset</button>
</div>
</template>
Here's an example implementation that will not work:
const EMPTY_FILTERS = { firstName: '', lastName: '' };
export default {
data() {
return { filtersFields: EMPTY_FILTERS };
},
methods: {
onReset() {
this.filtersFields = EMPTY_FILTERS;
},
},
};
This fails because this.filtersFields = EMPTY_FILTERS actually does nothing. Object assignment in JS is done by reference, so filtersFields already points to EMPTY_FILTERS. Here's an example that does work:
const EMPTY_FILTERS = { firstName: '', lastName: '' };
export default {
data() {
return { filtersFields: { ...EMPTY_FILTERS } };
},
methods: {
onReset() {
this.filtersFields = { ...EMPTY_FILTERS };
},
},
};
This time we are always assigning a copy of EMPTY_FILTERS, which will correctly be observed by Vue.
I had a similar issue like this once. It is because (depending on how you are assigning the initial state) you are probably still observing the same object.
Try recreating the object that you want to assign on each assignment.
const emptyFilters = {
name: ''
};
export default class MyComponent extends Vue {
methods: {
setFilters () {
let filters = JSON.parse(JSON.stringify(emptyFilters));
this.$set(this, 'filtersFields', filters);
},
},
};
Why do I get this error:
Error [vuex] Do not mutate vuex store state outside mutation handlers.
What does it mean?
It happens when I try to type in the edit input file.
pages/todos/index.vue
<template>
<ul>
<li v-for="todo in todos">
<input type="checkbox" :checked="todo.done" v-on:change="toggle(todo)">
<span :class="{ done: todo.done }">{{ todo.text }}</span>
<button class="destroy" v-on:click="remove(todo)">delete</button>
<input class="edit" type="text" v-model="todo.text" v-todo-focus="todo == editedTodo" #blur="doneEdit(todo)" #keyup.enter="doneEdit(todo)" #keyup.esc="cancelEdit(todo)">
</li>
<li><input placeholder="What needs to be done?" autofocus v-model="todo" v-on:keyup.enter="add"></li>
</ul>
</template>
<script>
import { mapMutations } from 'vuex'
export default {
data () {
return {
todo: '',
editedTodo: null
}
},
head () {
return {
title: this.$route.params.slug || 'all',
titleTemplate: 'Nuxt TodoMVC : %s todos'
}
},
fetch ({ store }) {
store.commit('todos/add', 'Hello World')
},
computed: {
todos () {
// console.log(this)
return this.$store.state.todos.list
}
},
methods: {
add (e) {
var value = this.todo && this.todo.trim()
if (value) {
this.$store.commit('todos/add', value)
this.todo = ''
}
},
toggle (todo) {
this.$store.commit('todos/toggle', todo)
},
remove (todo) {
this.$store.commit('todos/remove', todo)
},
doneEdit (todo) {
this.editedTodo = null
todo.text = todo.text.trim()
if (!todo.text) {
this.$store.commit('todos/remove', todo)
}
},
cancelEdit (todo) {
this.editedTodo = null
todo.text = this.beforeEditCache
},
},
directives: {
'todo-focus' (el, binding) {
if (binding.value) {
el.focus()
}
}
},
}
</script>
<style>
.done {
text-decoration: line-through;
}
</style>
stores/todos.js
export const state = () => ({
list: []
})
export const mutations = {
add (state, text) {
state.list.push({
text: text,
done: false
})
},
remove (state, todo) {
state.list.splice(state.list.indexOf(todo), 1)
},
toggle (state, todo) {
todo.done = !todo.done
}
}
Any ideas how I can fix this?
It could be a bit tricky to use v-model on a piece of state that belongs to Vuex.
and you have used v-model on todo.text here:
<input class="edit" type="text" v-model="todo.text" v-todo-focus="todo == editedTodo" #blur="doneEdit(todo)" #keyup.enter="doneEdit(todo)" #keyup.esc="cancelEdit(todo)">
use :value to read value and v-on:input or v-on:change to execute a method that perform the mutation inside an explicit Vuex mutation handler
This issue is handled here: https://vuex.vuejs.org/en/forms.html
Hello I have get the same problem and solve it with clone my object using one of the following:
{ ...obj} //spread syntax
Object.assign({}, obj)
JSON.parse(JSON.stringify(obj))
For your code I think you need to replace this part
computed: {
todos () {
// console.log(this)
return this.$store.state.todos.list
}
}
With this
computed: {
todos () {
// console.log(this)
return {...this.$store.state.todos.list}
}
}
I don't make sure if this is the best way but hope this helpful for other people that have the same issue.
This error may come from the fact you shallow cloned an object.
Meaning that you've tried to copy an object but an object is not a primitive type (like String or Number), hence it's passed by reference and not value.
Here you think that you cloned one object into the other, while you are still referencing the older one. Since you're mutating the older one, you got this nice warning.
Here is a GIF from Vue3's documentation (still relevant in our case).
On the left, it's showing an object (mug) being not properly cloned >> passed by reference.
On the right, it's properly cloned >> passed by value. Mutating this one does not mutate the original
The proper way to manage this error is to use lodash, this is how to load it efficiently in Nuxt:
Install lodash-es, eg: yarn add lodash-es, this is an optimized tree-shakable lodash ES module
you may also need to transpile it in your nuxt.config.js with the following
build: {
transpile: ['lodash-es'],
}
load it into your .vue components like this
<script>
import { cloneDeep } from 'lodash-es'
...
const properlyClonedObject = cloneDeep(myDeeplyNestedObject)
...
</script>
Few keys points:
lodash is recommended over JSON.parse(JSON.stringify(object)) because it does handle some edge-cases
we only load small functions from lodash and not the whole library thanks to this setup, so there is no penalty in terms of performance
lodash has a lot of well battle-tested useful functions, which is heavily lacking in JS (no core library)
UPDATE: structuredClone is also native and quite performant if you're looking for a solution for a deep copy, bypassing the need for Lodash at all.
There is no headache if you can use lodash
computed: {
...mapState({
todo: (state) => _.cloneDeep(state.todo)
})
}
Just in case someone's still being troubled by this,
I got my code working by making a duplicate/clone of the store state.
In your case, try something like this...
computed: {
todos () {
return [ ...this.$store.state.todos.list ]
}
}
It's basically a spread operator which results in making a clone of the todos.list array. With that, you're not directly changing the values of your state, just don't forget commit so your mutations will be saved in the store.
export default new Vuex.Store({
...
strict: true
})
try to comment "strict"
If you are using Vuex Modules, you might bump into this error if your module's data property is an object, instead of a function that returns an object, and you are sharing this Module between more than one Store.
So instead of:
// In stores/YourModule.js
export default {
state: { name: 'Foo' },
}
Change it to:
// In stores/YourModule.js
export default {
state: () => {
return { name: 'Foo' };
},
}
This is actually documented here:
Sometimes we may need to create multiple instances of a module, for
example:
Creating multiple stores that use the same module (e.g. To avoid
stateful singletons in the SSR (opens new window)when the
runInNewContext option is false or 'once'); Register the same module
multiple times in the same store. If we use a plain object to declare
the state of the module, then that state object will be shared by
reference and cause cross store/module state pollution when it's
mutated.
This is actually the exact same problem with data inside Vue
components. So the solution is also the same - use a function for
declaring module state (supported in 2.3.0+):
If your data is an array with objects inside. Below snippet is the solution
const toyData = await this.$store.dispatch(
`user/fetchCoinToys`,
payload
)
const msgList = toyData.msglist.map((data) => {
return { ...data }
})
I had to add mutation and call it instead of setting directly.
wrong:
someAction({state, rootState}) {
state.someValue = true;
}
right:
mutations: {
...
setSomeValue(state, val) {
state.someValue = val;
},
...
}
...
someAction({state, commit, rootState}) {
commit('setSomeValue', true);
}
It is not your case but if someone is using typescript and is having the same problem, adding this: any as the first param in your method or somewhere else should fix the problem
As far as I know vuex-router-sync is just for synchronizing the route with the vuex store and the developer can access the route as follows:
store.state.route.path
store.state.route.params
However, I can also handle route by this.$route which is more concise.
When do I need to use the route in the store, and what is the scenario in which I need vuex-router-sync?
Here's my two cents. You don't need to import vuex-router-sync if you cannot figure out its use case in your project, but you may want it when you are trying to use route object in your vuex's method (this.$route won't work well in vuex's realm).
I'd like to give an example here.
Suppose you want to show a message in one component. You want to display a message like Have a nice day, Jack in almost every page, except for the case that Welcome back, Jack should be displayed when the user's browsing top page.
You can easily achieve it with the help of vuex-router-sync.
const Top = {
template: '<div>{{message}}</div>',
computed: {
message() {
return this.$store.getters.getMessage;
}
},
};
const Bar = {
template: '<div>{{message}}</div>',
computed: {
message() {
return this.$store.getters.getMessage;
}
}
};
const routes = [{
path: '/top',
component: Top,
name: 'top'
},
{
path: '/bar',
component: Bar,
name: 'bar'
},
];
const router = new VueRouter({
routes
});
const store = new Vuex.Store({
state: {
username: 'Jack',
phrases: ['Welcome back', 'Have a nice day'],
},
getters: {
getMessage(state) {
return state.route.name === 'top' ?
`${state.phrases[0]}, ${state.username}` :
`${state.phrases[1]}, ${state.username}`;
},
},
});
// sync store and router by using `vuex-router-sync`
sync(store, router);
const app = new Vue({
router,
store,
}).$mount('#app');
// vuex-router-sync source code pasted here because no proper cdn service found
function sync(store, router, options) {
var moduleName = (options || {}).moduleName || 'route'
store.registerModule(moduleName, {
namespaced: true,
state: cloneRoute(router.currentRoute),
mutations: {
'ROUTE_CHANGED': function(state, transition) {
store.state[moduleName] = cloneRoute(transition.to, transition.from)
}
}
})
var isTimeTraveling = false
var currentPath
// sync router on store change
store.watch(
function(state) {
return state[moduleName]
},
function(route) {
if (route.fullPath === currentPath) {
return
}
isTimeTraveling = true
var methodToUse = currentPath == null ?
'replace' :
'push'
currentPath = route.fullPath
router[methodToUse](route)
}, {
sync: true
}
)
// sync store on router navigation
router.afterEach(function(to, from) {
if (isTimeTraveling) {
isTimeTraveling = false
return
}
currentPath = to.fullPath
store.commit(moduleName + '/ROUTE_CHANGED', {
to: to,
from: from
})
})
}
function cloneRoute(to, from) {
var clone = {
name: to.name,
path: to.path,
hash: to.hash,
query: to.query,
params: to.params,
fullPath: to.fullPath,
meta: to.meta
}
if (from) {
clone.from = cloneRoute(from)
}
return Object.freeze(clone)
}
.router-link-active {
color: red;
}
<script src="https://unpkg.com/vue/dist/vue.js"></script>
<script src="https://unpkg.com/vue-router/dist/vue-router.js"></script>
<script src="https://unpkg.com/vuex/dist/vuex.js"></script>
<div id="app">
<p>
<router-link to="/top">Go to Top</router-link>
<router-link to="/bar">Go to Bar</router-link>
</p>
<router-view></router-view>
</div>
fiddle here
As you can see, the components are well decoupled from vuex and vue-router's logic.
This pattern sometimes works really effectively for the case that you're not concerned about the relationship between current route and the value returned from vuex's getter.
I saw this thread when I was learning Vue. Added some of my understanding on the question.
Vuex defines a state management pattern for Vue applications. Instead of defining component props and passing the shared state through props in all the places, we use a centralized store to organize the state shared by multiple components. The restriction on state mutation makes the state transition clearer and easier to reason about.
Ideally, we should get / build consistent (or identical) views if the provided store states are the same. However, the router, shared by multiple components, breaks this. If we need to reason about why the page is rendered like it is, we need to check the store state as well as the router state if we derive the view from the this.$router properties.
vuex-router-sync is a helper to sync the router state to the centralized state store. Now all the views can be built from the state store and we don't need to check this.$router.
Note that the route state is immutable, and we should "change" its state via the $router.push or $router.go call. It may be helpful to define some actions on store as:
// import your router definition
import router from './router'
export default new Vuex.Store({
//...
actions: {
//...
// actions to update route asynchronously
routerPush (_, arg) {
router.push(arg)
},
routerGo (_, arg) {
router.go(arg)
}
}
})
This wraps the route updates in the store actions and we can completely get rid of the this.$router dependencies in the components.