- Global Config silent optionMergeStrategies devtools errorHandler ignoredElements keyCodes.
- Are you targeting the correct property: Updating a property in Vuex state. When your Vue application starts to become more complex, and you have things that are named similarly, and perhaps more nesting than is healthy in your data structures, it can be easy to target the incorrect property when you are mutating the state.
NOTE
Vuex module to interface with AWS Cognito. Install: npm install @vuetify/vuex-cognito-module yarn add @vuetify/vuex-cognito-module # Vue. Import into your project's.
This is the docs for Vuex 4, which works with Vue 3. If you're looking for docs for Vuex 3, which works with Vue 2, please check it out here.
Vuex is a state management pattern + library for Vue.js applications. It serves as a centralized store for all the components in an application, with rules ensuring that the state can only be mutated in a predictable fashion.
# What is a 'State Management Pattern'?
Let's start with a simple Vue counter app:
It is a self-contained app with the following parts:
- The state, the source of truth that drives our app;
- The view, a declarative mapping of the state;
- The actions, the possible ways the state could change in reaction to user inputs from the view.
This is a simple representation of the concept of 'one-way data flow':
However, the simplicity quickly breaks down when we have multiple components that share a common state:
- Multiple views may depend on the same piece of state.
- Actions from different views may need to mutate the same piece of state.
For problem one, passing props can be tedious for deeply nested components, and simply doesn't work for sibling components. For problem two, we often find ourselves resorting to solutions such as reaching for direct parent/child instance references or trying to mutate and synchronize multiple copies of the state via events. Both of these patterns are brittle and quickly lead to unmaintainable code.
So why don't we extract the shared state out of the components, and manage it in a global singleton? With this, our component tree becomes a big 'view', and any component can access the state or trigger actions, no matter where they are in the tree!
By defining and separating the concepts involved in state management and enforcing rules that maintain independence between views and states, we give our code more structure and maintainability.
This is the basic idea behind Vuex, inspired by Flux, Redux and The Elm Architecture. Unlike the other patterns, Vuex is also a library implementation tailored specifically for Vue.js to take advantage of its granular reactivity system for efficient updates.
If you want to learn Vuex in an interactive way you can check out this Vuex course on Scrimba, which gives you a mix of screencast and code playground that you can pause and play around with anytime.
# When Should I Use It?
Vuex helps us deal with shared state management with the cost of more concepts and boilerplate. It's a trade-off between short term and long term productivity.
Vuex Cheat Sheet Pdf
If you've never built a large-scale SPA and jump right into Vuex, it may feel verbose and daunting. That's perfectly normal - if your app is simple, you will most likely be fine without Vuex. A simple store pattern may be all you need. But if you are building a medium-to-large-scale SPA, chances are you have run into situations that make you think about how to better handle state outside of your Vue components, and Vuex will be the natural next step for you. There's a good quote from Dan Abramov, the author of Redux:
Flux libraries are like glasses: you’ll know when you need them.
Vuex Cheat Sheet
- ```js
- modules: {
- state: {
- },
- square(state) {
- }
- mutations: {
- state.count++;
- setNewValue(state, newValue) {
- },
- actions: {
- return someApi.getCount()
- commit('setNewValue', newCount);
- },
- },
- },
- ```
- ## State
- **Never** manipulate state directly, use a mutation or action for that.
- Example accessing the store from a component:
- ```js
- template: `<div>{{ count }}</div>`,
- count () {
- }
- }
- ### Accessing State
- ```js
- ```
- ```js
- console.log(this.$store.counter.count);
- Retrieve computed derived state based on the store.
- Getter functions receive the following positional arguments:
- ```
- state, // will be module local state if defined in a module.
- getters, // module local getters of the current module
- rootState, // global state (only available in a module)
- rootGetters // all getters (only available in a module)
- Root level access:
- console.log(store.getters.fooBar);
- ```js
- // ...
- return state.todos.find(todo => todo.id id)
- }
- store.getters.getTodoById(2) // -> { id: 2, text: '...', done: false }
- ```js
- ```
- The only way to change state is through a mutation. Mutations are
- Mutation functions in the Store receive positional arguments:
- - `payload` - Optional payload is whatever (if anything) is passed to
- mutations: {
- state.count++;
- },
- To invoke a mutation, use the `commit()` function.
- ```js
- ```
- ```js
- this.$store.commit('counter/setNewValue', 22);
- Actions are like **asynchronous** mutations.
- - Instead of mutating the state, actions commit mutations.
- - Actions can contain arbitrary asynchronous operations.
- Action functions receives positional arguments `context` and `payload`.
- `context` looks like this:
- {
- state, // same as `store.state`, or local state if in modules
- rootState, // same as `store.state`, only in modules
- dispatch, // same as `store.dispatch`
- getters, // same as `store.getters`, or local getters if in modules
- rootGetters // same as `store.getters`, only in modules
- ```
- `payload` is optional if passed as the second argument to `dispatch()`.
- Actions should `commit` any changes via a mutation.
- const actions = {
- return someApi.getCount()
- commit('setNewValue', newCount);
- },
- ```
- ### Dispatch
- Dispatch can also take a `payload` as a second argument.
- ```js
- ```