README based on EnvVarProvider

Signed-off-by: MattIPv4 <me@mattcowley.co.uk>

Author: MattIPv4

libs/providers/localstorage/README.md

@@ -1,15 +1,104 @@
-# localstorage Provider
+# LocalStorage Provider
+
+The `localStorage` provider is a great provider to use combined with other providers to allow for local overrides of feature flags.
+It doesn't require any infrastructure to setup or manage, and provides a simple way to allow anyone with access to the browser's developer tools to change the values of feature flags for their own experience.
+This could be useful for testing or debugging purposes, or as part of a minimal hidden UI in your application to allow developers, product managers, or anyone else, to self-serve their own access to features in development.
 
 ## Installation
 
 ```
 $ npm install @openfeature/localstorage-provider
 ```
 
-## Building
+Required peer dependencies
+
+```
+$ npm install @openfeature/web-sdk
+```
+
+## Usage
+
+The `localStorage` provider uses the browser's `localStorage` to determine the value of a feature flag.
+It supports `booleans`, `strings`, `numbers` and `objects` by attempting to interpret the value of a `localStorage` entry to the requested type.
+The default value will be returned if there is no matching `localStorage` entry or the value can't be cast to the desired type.
+
+```typescript
+import { OpenFeature, MultiProvider } from '@openfeature/web-sdk';
+import { LocalStorageProvider } from '@openfeature/localstorage-provider';
+
+// Register the localStorage provider globally, combined with any other providers you may be using
+OpenFeature.setProvider(
+  new MultiProvider([{ provider: new LocalStorageProvider() }, { provider: new OtherProvider() }]),
+);
+```
+
+### Available options
+
+| Option name | Type   | Default        |
+| ----------- | ------ | -------------- |
+| prefix      | string | 'openfeature.' |
+
+Use the `prefix` option to specify a custom prefix for `localStorage` entries.
+By default, the provider will look for entries that start with `openfeature.`, followed by the flag key.
+For example, if you have a flag with the key `new-feature`, the provider will look for a `localStorage` entry with the key `openfeature.new-feature` to determine the value of that flag.
+This allows you to define feature flags in `localStorage` without worrying about naming collisions with other data stored there.
+
+## Examples
+
+### Boolean example
+
+```javascript
+// In the browser's developer console set a localStorage entry for the flag
+localStorage.setItem('openfeature.enable-new-feature', 'true');
+```
+
+```typescript
+const client = OpenFeature.getClient();
+client.getBooleanValue('enable-new-feature', false);
+```
+
+### Number example
+
+```javascript
+// In the browser's developer console set a localStorage entry for the flag
+localStorage.setItem('openfeature.difficulty-multiplier', '5');
+```
+
+```typescript
+const client = OpenFeature.getClient();
+client.getNumberValue('difficulty-multiplier', 0);
+```
+
+### String example
+
+```javascript
+// In the browser's developer console set a localStorage entry for the flag
+localStorage.setItem('openfeature.welcome-message', 'yo');
+```
+
+```typescript
+const client = OpenFeature.getClient();
+client.getStringValue('welcome-message', 'hi');
+```
+
+### Object example
+
+```javascript
+// In the browser's developer console set a localStorage entry for the flag
+localStorage.setItem('openfeature.preferred-sdk', '{"name": "openfeature"}');
+```
+
+```typescript
+const client = OpenFeature.getClient();
+client.getObjectValue('preferred-sdk', { name: 'OpenFeature' });
+```
+
+## Development
+
+### Building
 
 Run `nx package providers-localstorage` to build the library.
 
-## Running unit tests
+### Running unit tests
 
 Run `nx test providers-localstorage` to execute the unit tests via [Jest](https://jestjs.io).