neat

Author: dmarticus

playground/nextjs/src/posthog.ts

@@ -67,6 +67,7 @@ if (typeof window !== 'undefined') {
         opt_in_site_apps: true,
         __preview_remote_config: true,
         __preview_experimental_cookieless_mode: false,
+        __preview_flags_v2: true,
         ...configForConsent(),
     })
     // Help with debugging

src/__tests__/__snapshots__/config-snapshot.test.ts.snap

@@ -502,6 +502,11 @@ exports[`config snapshot for PostHogConfig 1`] = `
     \\"false\\",
     \\"true\\"
   ],
+  \\"__preview_flags_v2\\": [
+    \\"undefined\\",
+    \\"false\\",
+    \\"true\\"
+  ],
   \\"api_method\\": [
     \\"undefined\\",
     \\"string\\"

src/posthog-featureflags.ts

@@ -390,6 +390,10 @@ export class PostHogFeatureFlags {
             data.disable_flags = true
         }
 
+        // NB: flags v2 requires remote config to be enabled as well, since the idea is that we will skip calling /decide altogether
+        // (which remote config does) and just use the /flags endpoint.  May revisit this if we need to support flags v2 without remote config
+        // (e.g. we could call `/decide` with flags disabled for the data otherwise returned by remote config, and then still call
+        // `/flags/` to get the flag evaluation data).
         const eligibleForFlagsV2 =
             this.instance.config.__preview_flags_v2 && this.instance.config.__preview_remote_config
 
@@ -415,8 +419,8 @@ export class PostHogFeatureFlags {
 
                 this._requestInFlight = false
 
+                // NB: this block is only reached if this.instance.config.__preview_remote_config is false
                 if (!this._decideCalled) {
-                    // NB: this will be true if remote config is enabled, which it is for the default posthog app api key
                     this._decideCalled = true
                     this.instance._onRemoteConfig(response.json ?? {})
                 }