feat(analytics): PostHog support (#1072)

docs/configuration.md

@@ -29,6 +29,7 @@ This part of the configuration concerns anything that can affect the whole site.
   - `{ provider: 'plausible' }` (managed) or `{ provider: 'plausible', host: '<your-plausible-host>' }` (self-hosted): use [Plausible](https://plausible.io/);
   - `{ provider: 'umami', host: '<your-umami-host>', websiteId: '<your-umami-website-id>' }`: use [Umami](https://umami.is/);
   - `{ provider: 'goatcounter', websiteId: 'my-goatcounter-id' }` (managed) or `{ provider: 'goatcounter', websiteId: 'my-goatcounter-id', host: 'my-goatcounter-domain.com', scriptSrc: 'https://my-url.to/counter.js' }` (self-hosted) use [GoatCounter](https://goatcounter.com)
+  - `{ provider: 'posthog', apiKey: '<your-posthog-project-apiKey>', host: '<your-posthog-host>' }`: use [Posthog](https://posthog.com/);
 - `locale`: used for [[i18n]] and date formatting
 - `baseUrl`: this is used for sitemaps and RSS feeds that require an absolute URL to know where the canonical 'home' of your site lives. This is normally the deployed URL of your site (e.g. `quartz.jzhao.xyz` for this site). Do not include the protocol (i.e. `https://`) or any leading or trailing slashes.
   - This should also include the subpath if you are [[hosting]] on GitHub pages without a custom domain. For example, if my repository is `jackyzha0/quartz`, GitHub pages would deploy to `https://jackyzha0.github.io/quartz` and the `baseUrl` would be `jackyzha0.github.io/quartz`.

quartz/cfg.ts

@@ -25,6 +25,11 @@ export type Analytics =
       host?: string
       scriptSrc?: string
     }
+  | {
+      provider: "posthog"
+      apiKey: string
+      host?: string
+    }
 
 export interface GlobalConfiguration {
   pageTitle: string

quartz/plugins/emitters/componentResources.ts

@@ -129,6 +129,13 @@ function addGlobalPageResources(ctx: BuildCtx, componentResources: ComponentReso
         "https://${cfg.analytics.websiteId}.${cfg.analytics.host ?? "goatcounter.com"}/count")
       document.head.appendChild(goatcounterScript)
     `)
+  } else if (cfg.analytics?.provider === "posthog") {
+    componentResources.afterDOMLoaded.push(`
+      const posthogScript = document.createElement("script")
+      posthogScript.innerHTML= \`!function(t,e){var o,n,p,r;e.__SV||(window.posthog=e,e._i=[],e.init=function(i,s,a){function g(t,e){var o=e.split(".");2==o.length&&(t=t[o[0]],e=o[1]),t[e]=function(){t.push([e].concat(Array.prototype.slice.call(arguments,0)))}}(p=t.createElement("script")).type="text/javascript",p.async=!0,p.src=s.api_host+"/static/array.js",(r=t.getElementsByTagName("script")[0]).parentNode.insertBefore(p,r);var u=e;for(void 0!==a?u=e[a]=[]:a="posthog",u.people=u.people||[],u.toString=function(t){var e="posthog";return"posthog"!==a&&(e+="."+a),t||(e+=" (stub)"),e},u.people.toString=function(){return u.toString(1)+".people (stub)"},o="capture identify alias people.set people.set_once set_config register register_once unregister opt_out_capturing has_opted_out_capturing opt_in_capturing reset isFeatureEnabled onFeatureFlags getFeatureFlag getFeatureFlagPayload reloadFeatureFlags group updateEarlyAccessFeatureEnrollment getEarlyAccessFeatures getActiveMatchingSurveys getSurveys onSessionId".split(" "),n=0;n<o.length;n++)g(u,o[n]);e._i.push([i,s,a])},e.__SV=1)}(document,window.posthog||[]);
+      posthog.init('${cfg.analytics.apiKey}',{api_host:'${cfg.analytics.host ?? "https://app.posthog.com"}'})\`
+      document.head.appendChild(posthogScript)
+    `)
   }
 
   if (cfg.enableSPA) {