Add dark theme

public/script.js

@@ -1,4 +1,6 @@
 import { toClipboard } from 'https://cdn.jsdelivr.net/npm/copee@1.0.6/dist/copee.mjs';
+const nowBlack = 'https://assets.zeit.co/image/upload/front/assets/design/now-black.svg';
+const nowWhite = 'https://assets.zeit.co/image/upload/front/assets/design/now-white.svg';
 
 function debounce(func, wait) {
 	var timeout;
@@ -86,6 +88,11 @@ const Toast = ({ show, message }) => {
     );
 }
 
+const themeOptions = [
+    { text: 'Light', value: 'light' },
+    { text: 'Dark', value: 'dark' },
+];
+
 const fileTypeOptions = [
     { text: 'PNG', value: 'png' },
     { text: 'JPEG', value: 'jpeg' },
@@ -103,19 +110,24 @@ const markdownOptions = [
 ];
 
 const App = (props, state, setState) => {
-    const setLoadingState = (newState) => setState({ ...newState, loading: true });
+    const setLoadingState = (newState) => {
+        
+        setState({ ...newState, loading: true });
+    };
     const {
         fileType = 'png',
         fontSize = '75px',
+        theme = 'light',
         md = '1',
         text = '**Hello** World',
-        images=['https://assets.zeit.co/image/upload/front/assets/design/now-black.svg'],
+        images=[nowBlack],
         showToast = false,
         messageToast = '',
         loading = true
     } = state;
     const url = new URL(window.location.hostname === 'localhost' ? 'https://og-image.now.sh' : window.location.origin);
     url.pathname = `${encodeURIComponent(text)}.${fileType}`;
+    url.searchParams.append('theme', theme);
     url.searchParams.append('md', md);
     url.searchParams.append('fontSize', fontSize);
     for (let image of images) {
@@ -127,6 +139,21 @@ const App = (props, state, setState) => {
         H('div',
             { className: 'pull-left' },
             H('div',
+                H(Field, {
+                    label: 'Theme',
+                    input: H(Dropdown, {
+                        options: themeOptions,
+                        value: theme,
+                        onchange: val => {
+                            if (images[0] === nowBlack && val === 'dark') {
+                                images[0] = nowWhite;
+                            } else if (images[0] === nowWhite && val === 'light') {
+                                images[0] = nowBlack;
+                            }
+                            setLoadingState({ theme: val, images: [...images] });
+                        }
+                    })
+                }),
                 H(Field, {
                     label: 'File Type',
                     input: H(Dropdown, { options: fileTypeOptions, value: fileType, onchange: val => setLoadingState({fileType: val}) })

src/parser.ts

@@ -4,10 +4,15 @@ import { parse } from 'url';
 export function parseRequest(req: IncomingMessage) {
     console.log('HTTP ' + req.url);
     const { pathname = '/', query = {} } = parse(req.url || '', true);
-    const { fontSize, images, md } = query;
+    const { fontSize, images, theme, md } = query;
     if (Array.isArray(fontSize)) {
         throw new Error('Expected a single fontSize');
     }
+    if (Array.isArray(theme)) {
+        throw new Error('Expected a single theme');
+    }
+
+    
     const arr = pathname.slice(1).split('.');
     let extension = '';
     let text = '';
@@ -23,11 +28,20 @@ export function parseRequest(req: IncomingMessage) {
     const parsedRequest: ParsedRequest = {
         type: extension === 'jpeg' ? extension : 'png',
         text: decodeURIComponent(text),
+        theme: theme === 'dark' ? 'dark' : 'light',
         md: md === '1' || md === 'true',
         fontSize: fontSize || '75px',
-        images: Array.isArray(images) && images.length > 0
+        images: Array.isArray(images) ? images : [images],
-            ? images
-            : ['https://assets.zeit.co/image/upload/front/assets/design/now-black.svg'],
     };
+    parsedRequest.images = getDefaultImages(parsedRequest.images, parsedRequest.theme);
     return parsedRequest;
 }
+
+function getDefaultImages(images: string[], theme: Theme) {
+    if (images.length > 0 && /^http/.test(images[0])) {
+        return images;
+    }
+    return theme === 'light'
+    ? ['https://assets.zeit.co/image/upload/front/assets/design/now-black.svg']
+    : ['https://assets.zeit.co/image/upload/front/assets/design/now-white.svg'];
+}

src/sanitizer.ts

@@ -8,6 +8,6 @@ const entityMap: { [key: string]: string } = {
 };
 
 export function sanitizeHtml(html: string) {
-    return html.replace(/[&<>"'\/]/g, key => entityMap[key]);
+    return String(html).replace(/[&<>"'\/]/g, key => entityMap[key]);
 }
 

src/template.ts

@@ -3,9 +3,15 @@ import { readFileSync } from 'fs';
 import * as marked from 'marked';
 import { sanitizeHtml } from './sanitizer';
 
-function getCss(fontSize: string) {
+function getCss(theme: string, fontSize: string) {
     const regular = readFileSync(`${__dirname}/../fonts/Inter-UI-Regular.woff2`).toString('base64');
     const bold = readFileSync(`${__dirname}/../fonts/Inter-UI-Bold.woff2`).toString('base64');
+    let background = 'white';
+    let foreground = 'black';
+
+    if (theme === 'dark') {
+        [foreground, background] = [background, foreground];
+    }
     return `
     @font-face {
         font-family: 'Inter UI';
@@ -22,7 +28,7 @@ function getCss(fontSize: string) {
     }
 
     body {
-        background: white;
+        background: ${background};
         background-image: radial-gradient(lightgray 5%, transparent 0);
         background-size: 60px 60px;
         height: 100vh;
@@ -59,18 +65,19 @@ function getCss(fontSize: string) {
         font-family: 'Inter UI', sans-serif;
         font-size: ${sanitizeHtml(fontSize)};
         font-style: normal;
+        color: ${foreground}
     }`;
 }
 
 export function getHtml(parsedReq: ParsedRequest) {
-    const { text, md, fontSize, images } = parsedReq;
+    const { text, theme, md, fontSize, images } = parsedReq;
     return `<!DOCTYPE html>
 <html>
     <meta charset="utf-8">
     <title>Generated Image</title>
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <style>
-        ${getCss(fontSize)}
+        ${getCss(theme, fontSize)}
     </style>
     <body>
         <div>

src/types.d.ts

@@ -1,8 +1,10 @@
 type ScreenshotType = 'png' | 'jpeg';
+type Theme = 'light' | 'dark';
 
 interface ParsedRequest {
     type: ScreenshotType;
     text: string;
+    theme: Theme;
     md: boolean;
     fontSize: string;
     images: string[];