Working with Getters in Nuxt.js Vuex

1. Introduction

In this tutorial, we aim to get you accustomed to using getters in Vuex within a Nuxt.js context. You will learn the basic concepts of Vuex getters and how to implement them effectively in your Nuxt.js applications.

By the end of the tutorial, you will be able to:
- Understand what Vuex getters are
- Create and use getters in your Nuxt.js Vuex store
- Apply best practices for working with getters

Prerequisites for this tutorial include a basic understanding of JavaScript, Vue.js, Vuex, and Nuxt.js.

2. Step-by-Step Guide

In Vuex, getters are like computed properties for stores. They allow you to derive some state based on store state.

Creating a Getter

In the Vuex store, you create getters in the getters object.

export const state = () => ({
  counter: 0
})

export const getters = {
  doubleCounter: state => {
    return state.counter * 2
  }
}

In the above example, doubleCounter is a getter that returns the double of the counter state.

Accessing a Getter

You can access getters in your components using this.$store.getters['getterName'].

computed: {
  doubleCount() {
    return this.$store.getters['doubleCounter']
  }
}

In the above example, doubleCount computed property will always return the double of the counter state.

3. Code Examples

Here are some practical examples.

Example 1: Simple Getter

// store/index.js
export const state = () => ({
  todos: [
    { id: 1, text: 'Learn Nuxt', done: false },
    { id: 2, text: 'Learn Vuex', done: true }
  ]
})

export const getters = {
  doneTodos: state => {
    return state.todos.filter(todo => todo.done)
  }
}

In this example, doneTodos getter will return only the todos that are marked as done.

Example 2: Getter Using Another Getter

// store/index.js
export const getters = {
  doneTodos: state => {
    return state.todos.filter(todo => todo.done)
  },
  doneTodosCount: (state, getters) => {
    return getters.doneTodos.length
  }
}

In this example, doneTodosCount getter is using doneTodos getter to calculate the number of todos that are done.

4. Summary

In this tutorial, you have learned about Vuex getters and how to use them effectively in your Nuxt.js applications. You have learned how to create getters, how to access them in your components, and how to use one getter within another.

As next steps, consider exploring more about Vuex actions and mutations, as getters often work in tandem with these features. The official Vuex documentation is a great resource for this.

5. Practice Exercises

Exercise 1: Basic Getter

Create a getter activeUsers that returns users who are marked as active from the users state.

Exercise 2: Getter Using Another Getter

Modify the activeUsers getter to return only the first 5 active users. Create another getter activeUsersCount that uses activeUsers to calculate the number of active users.

Exercise 3: Getter with Arguments

Create a getter getUserById that accepts an id and returns the user with that id.

Solutions:

1. activeUsers getter:

export const getters = {
  activeUsers: state => {
    return state.users.filter(user => user.active)
  }
}

1. Modifying activeUsers and creating activeUsersCount:

export const getters = {
  activeUsers: state => {
    return state.users.filter(user => user.active).slice(0, 5)
  },
  activeUsersCount: (state, getters) => {
    return getters.activeUsers.length
  }
}

1. getUserById getter:

export const getters = {
  getUserById: (state) => (id) => {
    return state.users.find(user => user.id === id)
  }
}

This getUserById getter can be used in your components like this: this.$store.getters['getUserById'](userId).

Remember, practice is key to mastering any concept. Try creating more complex getters and using them in your Nuxt.js applications.