Pinia

by Pig Fang @g-plane

Create a type-level function whose types is similar to [Pinia](https://github.com/posva/pinia) library. You don't need to implement function actually, just adding types. ### Overview This function receive only one parameter whose type is an object. The object contains 4 properties: - `id` - just a string (required) - `state` - a function which will return an object as store's state (required) - `getters` - an object with methods which is similar to Vue's computed values or Vuex's getters, and details are below (optional) - `actions` - an object with methods which can do side effects and mutate state, and details are below (optional) ### Getters When you define a store like this: ```typescript const store = defineStore({ // ...other required fields getters: { getSomething() { return 'xxx' } } }) ``` And you should use it like this: ```typescript store.getSomething ``` instead of: ```typescript store.getSomething() // error ``` Additionally, getters can access state and/or other getters via `this`, but state is read-only. ### Actions When you define a store like this: ```typescript const store = defineStore({ // ...other required fields actions: { doSideEffect() { this.xxx = 'xxx' return 'ok' } } }) ``` Using it is just to call it: ```typescript const returnValue = store.doSideEffect() ``` Actions can return any value or return nothing, and it can receive any number of parameters with different types. Parameters types and return type can't be lost, which means type-checking must be available at call side. State can be accessed and mutated via `this`. Getters can be accessed via `this` but they're read-only.