use-cookie-state

A simple, yet flexible React hook for managing persistent state through browser cookies.
By leveraging browser cookies, use-cookie-state ensures that your component states remain consistent and available even after a page reload. It gracefully handles both client and server-side rendering (SSR) scenarios.

Key Highlights:

• Persistent state: Store your React state in browser cookies.
• Similar to useState: Familiar API and usage, making it intuitive for React developers.
• Flexible options: Customizable cookie settings, including maxAge, expires, domain, path, secure, httpOnly, sameSite, priority, and partitioned.
• SSR-friendly: Falls back to useState behavior when document.cookie is not accessible.

Table of Contents

• use-cookie-state
  • Table of Contents
  • Installation
  • API Reference
  • Cookie Options
    • Default Encode Options:
    • Other Encode Options:
  • Examples
    • Basic Usage
    • Handling Complex Data (JSON)
    • Custom Cookie Settings
    • Runtime Overrides
  • Server-Side Rendering (SSR)
  • Tips & Best Practices
  • License

Installation

Using npm:

npm install --save use-cookie-state cookie

Using yarn:

yarn add use-cookie-state cookie

Note: The cookie package is a peer dependency and must be installed alongside use-cookie-state.

API Reference

useCookieState<T = string>(
  key: string,
  initialValue: T,
  options?: {
    decode?: (value: string) => any; 
    encode?: CookieSerializeOptions;
  }
): [T, (value: T, encode?: CookieSerializeOptions) => void];

Parameters:

• key (string, required): Cookie name.
• initialValue (T, required): Initial state value. Can be a primitive, object, or a function returning the initial value.
• options (optional):
  • decode: A function to decode the cookie value when reading it from document.cookie.
  • encode: An object specifying default cookie attributes used when writing the cookie.

!IMPORTANT!: Due the cookie package implementation, the decode function will be applied for each cookie value, during the cookies parsing process. Be patient to use try/catch block to avoid errors.

Return Value:

• An array [value, setValue] similar to useState:
  • value: The current state derived from the cookie.
  • setValue(value: T, encode?: CookieSerializeOptions): Updates the cookie (and the state). Accepts optional runtime encode options to override defaults.

Cookie Options

When setting or updating cookies, you can specify cookie-related attributes as encode options. These options influence how the cookie is stored and retrieved by the browser. All cookie attributes are optional.

Default Encode Options:

If no encode options are provided, use-cookie-state defaults to:

{ path: "/", expires: new Date("9999") }

You can override these defaults by specifying your own encode options.

Other Encode Options:

• maxAge (number): Maximum age of the cookie in seconds. If both expires and maxAge are set, maxAge takes precedence.
• expires (Date): Specific date and time when the cookie should expire.
• domain (string): The domain for which the cookie is valid. Defaults to the current domain if not set.
• path (string): The path for which the cookie is valid. Defaults to "/".
• httpOnly (boolean): If true, the cookie is not accessible to client-side JavaScript.
• secure (boolean): If true, the cookie is only sent over HTTPS connections.
• sameSite (true | "strict" | "lax" | "none"): Controls cross-site request behavior.
  • true or "strict": Strict same-site enforcement.
  • "lax": Lax same-site enforcement.
  • "none": No same-site restrictions.
• priority ("low" | "medium" | "high"): Sets the cookie’s priority.
• partitioned (boolean): Enables the Partitioned attribute for the cookie (experimental).

You can find more details about these options in the cookie package documentation: CookieSerializeOptions.

Examples

Basic Usage

import React from "react";
import { useCookieState } from "use-cookie-state";

function MyComponent() {
  const [value, setValue] = useCookieState("username", "JohnDoe");

  return (
    <div>
      <div>Username: {value}</div>
      <button onClick={() => setValue("JaneDoe")}>Change Username</button>
    </div>
  );
}

export default MyComponent;

Handling Complex Data (JSON)

For objects/arrays, store as JSON and provide a decode function:

import React from "react";
import { useCookieState } from "use-cookie-state";

function jsonDecode(value) {
  try {
    return JSON.parse(value);
  } catch {
    return value;
  }
}

function MyComponent() {
  const [data, setData] = useCookieState("myData", { foo: "bar" }, { decode: jsonDecode });

  const updateData = () => {
    setData({ foo: "baz", count: 1 });
  };

  return (
    <div>
      <pre>{JSON.stringify(data, null, 2)}</pre>
      <button onClick={updateData}>Update Data</button>
    </div>
  );
}

export default MyComponent;

!IMPORTANT!: Due the cookie package implementation, the decode function will be applied for each cookie value, during the cookies parsing process. Be patient to use try/catch block to avoid errors.

Custom Cookie Settings

import React from "react";
import { useCookieState } from "use-cookie-state";

function MyComponent() {
  const [value] = useCookieState("myKey", "initialVal", {
    encode: {
      maxAge: 60 * 60 * 24 * 7, // 1 week
      secure: true,
      sameSite: "strict",
      httpOnly: true
    }
  });

  return <div>Value: {value}</div>;
}

export default MyComponent;

Runtime Overrides

import React from "react";
import { useCookieState } from "use-cookie-state";

function MyComponent() {
  const [state, setState] = useCookieState("userToken", "abc123", {
    encode: { secure: true, path: "/" }
  });

  const updateToken = () => {
    // Add domain at runtime, merging it with the default secure and path options
    setState("newTokenValue", { domain: "example.com" });
  };

  return (
    <div>
      <div>Current Token: {state}</div>
      <button onClick={updateToken}>Update Token</button>
    </div>
  );
}

export default MyComponent;

Server-Side Rendering (SSR)

On the server, document.cookie is not available. During SSR:

• useCookieState uses the provided initialValue directly, just like useState.
• No cookie operations occur until the browser environment is available.

Once hydrated, it will sync the component state with any browser cookies.

Tips & Best Practices

1. Keep cookie size small: Most cookies have size limits (~4KB).
2. Use JSON for complex data: Consider JSON.stringify on write and a custom decode function on read.
3. Security considerations: Use secure: true if your site uses HTTPS.
4. Domain and path: Control where cookies are valid with domain and path.
5. SameSite attribute: Consider sameSite to protect against CSRF attacks or to allow cross-site requests depending on your needs.

License

MIT © dqunbp