Vue Tip: Simple State Management With Composition API

You might think that you need a state management library like Pinia to manage your state, but that's not always the case. If you have a small application that only needs to share state between a few components, you can use the Composition API to create a simple state management solution.

Build a Simple State Management Solution

Let me show you how you can build a simple state management solution with the Composition API which contains state, mutations/actions, and getters.

Let's start by defining the state using a reactive object inside a useState.ts composable:

1const state = reactive({ counter: 0 })
2
3export const useState = () => {
4  return {}
5}

By lifting the state outside the composable function, it can be shared between multiple components. Read more at "Share Composable State Across Components".

Next, we need to define the mutations/actions that can update the state. All we need to do is to add a function that updates the state:

1const state = reactive({ counter: 0 })
2
3export const useState = () => {
4  function setCounter(value: number) {
5    state.counter = value
6  }
7
8  return { setCounter }
9}

For a getter, we can simply return the state:

1const state = reactive({ counter: 0 })
2
3export const useState = () => {
4  const count = computed(() => state.counter)
5  const doubleCount = computed(() => state.counter * 2)
6
7  return { count, doubleCount }
8}

Why Pinia?

You might wonder why you should use a store library like Pinia if you could just use the Composition API to build a simple state management solution. The answer is provided in Pinia documentation and here are some of the reasons. Pinia provides:

• Devtools support
• Hot module replacement
• Plugins: extend Pinia features with plugins
• Proper TypeScript support or autocompletion for JS users
• Server Side Rendering (SSR) Support

StackBlitz

You can try our simple state management solution in the following StackBlitz: