Understanding Vuex Mutations and Actions

Vuex is a state management pattern and library for Vue.js applications. It helps manage global state by providing a single source of truth for state, making it easier to reason about and debug applications. At the core of Vuex are mutations and actions, which are used to change the state of an application.

Mutations in Vuex

In Vuex, mutations are the only way to change the state of a store. They are simple and well-known to all Vuex users. Mutations are pure functions that receive input only via their payload and do not produce side effects elsewhere.

const mutations = {
  increment(state, payload) {
    state.count += payload.amount;
  }
};

They are intended to be focused on particular tasks, making it easier to debug and track changes to the state.

Actions in Vuex

Actions are similar to mutations but with some key differences. Instead of mutating the state directly, actions commit mutations. They can also contain arbitrary asynchronous operations. Actions are promisified by default, making it easy to handle asynchronous code.

const actions = {
  async fetchData({ commit }) {
    const response = await fetch('undefined.com/data');
    commit('setData', response.data);
  }
};

Using Mutations and Actions

When deciding whether to use a mutation or an action, consider the following guidelines:

• Use mutations when you need to make a simple change to the state.
• Use actions when you need to perform more complex logic, such as asynchronous operations or committing multiple mutations.

Best Practices

To get the most out of Vuex mutations and actions, follow these best practices:

• Keep mutations focused on particular tasks.
• Use actions to perform complex logic.
• Avoid using mutations as a layer without abstraction.
• Use actions to serve a functional role.

Advanced Techniques

For advanced use cases, consider the following techniques:

• Using async/await with actions.
• Merging mutations and actions into a single “mutaction”.
• Leveraging reactivity magic to create custom proxies.

const mutaction = {
  async incrementAndFetchData({ commit, state }) {
    commit('increment', { amount: 1 });
    const response = await fetch('https://example.com/data');
    commit('setData', response.data);
  }
};