add prop for disabling global style injection

.storybook/preview.js

@@ -1,16 +1,13 @@
 import React from 'react';
-import { injectGlobalStyles, ThemeProvider } from '../src';
+import { ThemeProvider } from '../src';
 
 export const parameters = {
   controls: { expanded: true },
   layout: 'fullscreen',
 };
 
-const { GlobalStyle } = injectGlobalStyles();
-
 const withThemeProvider = (Story) => (
   <ThemeProvider>
-    <GlobalStyle />
     <Story />
   </ThemeProvider>
 );

README.md

@@ -12,9 +12,13 @@ Install Spicy UI to your React project with `npm i @spicy-ui/core styled-compone
 
 ```js
 import React from 'react';
-import { Button } from '@spciy-ui/core';
+import { Button, ThemeProvider } from '@spciy-ui/core';
 
-export const App = () => <Button>Hey hot stuff 🌶️</Button>;
+export const App = () => (
+  <ThemeProvider>
+    <Button>Hey hot stuff 🌶️</Button>
+  </ThemeProvider>
+);
 ```
 
 See the [documentation](https://spicy-ui.netlify.app/) for components, theming and advanced usage.

src/components/Theme/ThemeProvider.tsx

@@ -2,17 +2,26 @@ import deepmerge from 'deepmerge';
 import * as React from 'react';
 import { ThemeProvider as StyledThemeProvider } from 'styled-components';
 import { theme as defaultTheme } from '../../theme';
+import { injectGlobalStyles } from './injectGlobalStyles';
+
+const { GlobalStyle } = injectGlobalStyles();
 
 export interface ThemeProps {
+  /**
+   * If you want to extend the global styles set to `true` and inject them
+   * manually via `injectGlobalStyles`.
+   */
+  disableInjection?: boolean;
   /** Custom theme to be merged with the default theme. */
   theme?: any;
 }
 
-export const ThemeProvider: React.FC<ThemeProps> = ({ children, theme = {} }) => {
+export const ThemeProvider: React.FC<ThemeProps> = ({ children, disableInjection, theme = {} }) => {
   const mergedTheme = React.useMemo(() => deepmerge(defaultTheme, theme), [theme]);
 
   return (
     <StyledThemeProvider theme={mergedTheme}>
+      {!disableInjection && <GlobalStyle />}
       <>{children}</>
     </StyledThemeProvider>
   );