Set baseUrl depending on the environment (#1526)

website/siteConfig.js

@@ -8,6 +8,10 @@
 // See https://docusaurus.io/docs/site-config.html for all the possible
 // site configuration options.
 
+// If BASE_URL environment variable is set, use it as baseUrl.
+// If on netlify, use '/'. Otherwise use '/KaTeX/'.
+const baseUrl = process.env.BASE_URL || (process.env.CONTEXT ? '/' : '/KaTeX/');
+
 /* List of projects/orgs using your project for the users page */
 const users = [
     {
@@ -22,7 +26,7 @@ const siteConfig = {
     title: 'KaTeX',
     tagline: 'The fastest math typesetting library for the web',
     url: 'https://khan.github.io',
-    baseUrl: '/KaTeX/',
+    baseUrl,
 
     // Used for publishing and more
     projectName: 'KaTeX',