grams

Granular ReActive Management of State

Description

A robust, granular, and well defined state management compatible with SOLID principles. A state manager that is reliable and consistent.

Define state once and utilize it throughout the app without much boilerplate.

Benefits:

• Atomic state
• Compatible with async actions
• Middleware compatibility
• Protected state
• Effect handling
• Structural state management

Supported Frameworks

• React (>=16.8.0)
• React Native (>=0.59)

To install:

yarn add grams

or

npm install grams

or

pnpm install grams

or

bun install grams

Definitions

Gram

Name	Description	Required	Type
defaultValue	Default initial value of state	Y	any
type	Type of state value	Y	"string" | "number" | "boolean" | "object" | "other"
stateType	Type of State	N	"stateful" | "stateic"
produce	Modifications or mutations of state	N	-
actions	Actions to execute (can be promises)	N	-
effects	Various effects (hooks) that run based on lifecycle	N	-
middleware	Functions that execute before a state change	N	-

State Types

Name	Description
stateful	A type of state that will cause a rerender
stateic	A type of state that will not cause a rerender (useful for static variables)

Effects

Name	Description
onMount	Runs after the state has been initialized. (Can be a promise and can modify the state on return)
onUpdate	Runs after the state has been updated. Cannot modify state directly.
onRender	Runs after the subscribed components have been rerendered. Cannot modify state directly.
onListenerSubscribed	Runs after a listener is subscribed. Cannot modify state directly.
onListenerUnSubscribed	Runs after a listener is unsubscribed. Cannot modify state directly.
onError	Runs if the state has failed. Cannot modify state directly.

Internal Functions

Name	Description
subscribe	A function that subscribes a listener to the state. (Components or functions can be subscribed.)
getState	A function that returns the current state.
setState	A function that sets the state and will execute all listeners. (Functions that are registered will rerender.)
getStateProduce	A function that returns a subset of the state.
action	A function that executes an action. (Can be used to execute actions without the need of hooks. Functions that are registered will rerender.)

Specifications

useStore

useStore() => [state, setState]

A hook that subscribes the component to the state, and returns the value of the state as well as its setter function. (Works similar to useState found in React hooks).

useStoreValue

useStoreValue() => state

A hook that subscribes the component to the state and only returns its value.

useSetStore

useSetStore() => setState

A hook that returns its setter function. It does not subscribe the component to the state.

useStoreProduce

useStoreProduce(produceName: string) => state

A hook that accepts the name of the produce, subscribes the component to the produce (subset) of the state, and returns its mutated value.

useStoreAction

useStoreAction(actionName: string) => setState

A hook that accepts the name of the action, and returns its action function. It does not subscribe the component to the state.

internal

{
    subscribe: (listener) => () => void;
    getState: () => state;
    setState: (newValue | ((prev) => newValue)) => void;
    getStateProduce: (key: string) => value;
    action: (key: string) => (newValue) => void;
}

State internal actions that can be used to manipulate the state without the need of hooks. These can be used to create custom hooks or actions or to run in instances where hooks cannot be used (i.e. query (fetch) functions, side effects etc).

Usage

1. Define the State

...

import { gram } from "grams";

...

const delay = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));

...

export const isAuthenticated = gram({
  defaultValue: false,
  type: "boolean",
  stateType: "stateful",
  produce: {
    isUnAuthenticated: (currValue) => !currValue,
  },
  actions: {
    login: () => true,
    logout: () => false,
  },
  effects: {
    onMount: async () => {
      isLoading.internal.setState(true);
      await delay(1000);
      isLoading.internal.setState(false);
      return true;
    },
  },
  middleware: {
    check: () => {
      console.log("auth middleware");
      return true;
    },
  },
});

2. Subscribe to the State or use the Actions

...

import { isAuthenticated } from "./store";

...

const ActionComponent = () => {
  const action = isAuthenticated.useStoreAction("logout");

  return <button onClick={action}>
    Logout
  </button>;
};

...

const ProduceComponent = () => {
  const isUnAuthenticated = isAuthenticated.useStoreProduce("isUnAuthenticated");

  return (
    <h1>Is Unauthenticated: {String(isUnAuthenticated)}</h1>
  );
};

...

const ValueComponent = () => {
  const isAuth = isAuthenticated.useStoreValue();

  return (
    <h1>Is Authenticated: {String(isAuth)}</h1>
  );
};

...

const Component = () => {
  const [isAuth, setIsAuth] = isAuthenticated.useStore();

  return (
    <div>
      <h1>Is Authenticated: {String(isAuth)}</h1>
      <button
        onClick={() => setIsAuth(true)}
      >
        Login
      </button>
    </div>
  );
};

Caveats

• Poor management, could lead to infinite state cycles - example listed below.

  const isAuthenticated = gram({
    defaultValue: false,
    type: "boolean",
    stateType: "stateful",
    ...
    effects: {
      ...
      onUpdate: async () => {
        isAuthenticated.internal.setState(true);
      }
    },
    ...
  });