store_api.md

initialize

This function initializes the state of the store.

It can receive one parameter: an initial state which is a JavaScript object. This parameter is optional and it's an empty object by default.

Example passing some initial state:

const initialState = {
  todos: [],
  visibilityFilter: VISIBILITY_FILTERS_SHOW_ALL,
  toast: {
    text: '',
    timeoutId: null,
    visible: false,
  }
};

store.initialize(initialState);

In this case the state of the store is set to the following object:

{
  todos: [],
  visibilityFilter: VISIBILITY_FILTERS_SHOW_ALL,
  toast: {
    text: '',
    timeoutId: null,
    visible: false,
  }
}

Example passing no initial state:

store.initialize();

In this case the state of the store is set to the following object:

{}

getState

This function gets the value of a piece of state at a given path.

It accepts only one parameter: a path. This parameter is optional and it's an empty array by default.

A path represents how to to get to the value in the app state we'd like to get. A path can be an array of strings like ['todos', 'status'] or a string in which each part of the path is separated by a dot, like 'todos.status'. In both cases, the piece of state being extracted would be appState.todos.status.

store.initialize({a: 1, b: {c: 3 d: {e: "h"}}});

store.getState(["a", "b", "c"]); // 3
store.getState("a.b.c"); // 3

store.getState("a.b.d"); // {e: "h"}

setState

This function sets the value of a piece of state at a given path.

It accepts only one parameter: an array of mutations.

Each mutation is an object comprised of two properties:

1. path: the path in the app state to get to the value we'd like to mutate. A path can be an array of strings like ['todos', 'status'] or a string in which each part of the path is separated by a dot, like 'todos.status'. In both cases, the piece of state being mutated would be appState.todos.status. If the path is empty, the function throws an exception.

2. newValue: the new value to be set.

Example:

store.initialize({a: 1, b: {c: 3 d: {e: "h"}}});

store.getState("a.b.d"); // {e: "h"}

store.setState({path: "a.b.d", newValue: 30});

store.getState("a.b.d"); // 30

If a mutation is successful, all the listeners subscribed to the store are executed.