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
No race conditions

Supported Frameworks

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

To install:

yarn add grams

npm 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"
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.
onUnMount	Runs after the state has been unmounted. Cannot modify state directly.
onError	Runs if the state has failed. Cannot modify state directly.

Specifications

useStore

useStore(key: string | ((stateKeys: StateKeys) => string)) => [state, setState]

A hook that accepts the key of the state, 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(key: string | ((stateKeys: StateKeys) => string)) => state

A hook that accepts the key of the state, subscribes the component to the state and only returns its value.

useSetStore

useSetStore(key: string | ((stateKeys: StateKeys) => string)) => setState

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

useStoreProduce

useStoreProduce(produceName: string | ((stateKeys: StateKeys) => string), key: string | ((stateKeys: StateKeys) => string)) => state

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

useStoreActions

useStoreActions(actionName: string | ((stateKeys: StateKeys) => string), key: string | ((stateKeys: StateKeys) => string)) => setState

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

Usage

1. Add the Provider to the root component

...

import { Provider } from "grams";

...

root.render(
    <Provider>
      <App />
    </Provider>
);

2. Define the State

...

import { gram } from "grams";

...

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

...

export const isAuthenticated = gram(
  false,
  "boolean",
  "stateful",
  {
    isUnAuthenticated: (currValue) => !currValue
  },
  {
    login: () => true,
    logout: () => false
  },
  {
    onMount: async (_, __, set) => {
      set(true, (storeKeys) => storeKeys.isLoading.key);
      await delay(1000);
      set(false, "isLoading");
      return true;
    }
  },
  {
    check: () => {
      console.log("auth middleware");
      return true;
    }
  }
);

3. Pass the State to the Provider

...

import { Provider } from "grams";

...

root.render(
    <Provider models={{ isAuthenticated, isLoading }}>
      <App />
    </Provider>
);

4. Subscribe to the State or use the Actions

...

import { useStoreActions, useStoreValue, useStoreProduce } from "grams";

...

const ActionComponent = () => {
  const login = useStoreActions("login", "isAuthenticated");

  return (
    <button
      onClick={() => {
        login();
      }}
    >
      Login
    </button>
  );
};

...

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

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

...

const ValueComponent = () => {
  const isAuthenticated = useStoreValue((storeKeys) => storeKeys.isAuthenticated.key);

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

...

const Component = () => {
  const [isAuthenticated, setIsAuthenticated] = useStore((storeKeys) => storeKeys.isAuthenticated.key);

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

Caveats

In StrictMode, the store does not function well due to limitations. For further information regarding StrictMode, visit React Docs.
- To avoid this, the recommended approach is to add the Provider above StrictMode:
```
root.render(
  <Provider models={{ isAuthenticated, isLoading }}>
    <StrictMode>
        <App />
    </StrictMode>
  </Provider>
);
```

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

const isAuthenticated = gram(
  false,
  "boolean",
  "stateful",
  {
    isUnAuthenticated: (currValue) => !currValue
  },
  {
    login: () => true,
    logout: () => false
  },
  {
    onMount: async (_, __, set) => {
      set(true, (storeKeys) => storeKeys.isAuthenticated.key);
      await delay(1000);
      set(false, (storeKeys) => storeKeys.isAuthenticated.key);
      return true;
    }
  },
  {
    check: () => {
      console.log("auth middleware");
      return true;
    }
  }
);

It could take time to setup the store. The store is created sequentially (one gram at a time) and if there are many grams defined, it could add overhead time.

HamzaKV/grams