feat(flags): Add remote config feature flag method that bypasses cach…

…ed values (#1729) * feat(flags): Add remote config feature flag method that bypasses cached values * Update src/posthog-featureflags.ts Co-authored-by: Phil Haack <[email protected]> --------- Co-authored-by: Phil Haack <[email protected]>
PostHog · Feb 14, 2025 · 5ec2fa0 · 5ec2fa0
1 parent 4676b05
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diff --git a/src/posthog-featureflags.ts b/src/posthog-featureflags.ts
@@ -9,6 +9,7 @@ import {
     JsonType,
     Compression,
     EarlyAccessFeature,
+    RemoteConfigFeatureFlagCallback,
 } from './types'
 import { PostHogPersistence } from './posthog-persistence'
 
@@ -359,6 +360,37 @@ export class PostHogFeatureFlags {
         return payloads[key]
     }
 
+    /*
+     * Fetches the payload for a remote config feature flag. This method will bypass any cached values and fetch the latest
+     * value from the PostHog API.
+     *
+     * Note: Encrypted remote config payloads will not be redacted, nor decrypted in the response.
+     *
+     * ### Usage:
+     *
+     *     getRemoteConfigPayload("home-page-welcome-message", (payload) => console.log(`Fetched remote config: ${payload}`))
+     *
+     * @param {String} key Key of the feature flag.
+     * @param {Function} [callback] The callback function will be called once the remote config feature flag payload has been fetched.
+     */
+    getRemoteConfigPayload(key: string, callback: RemoteConfigFeatureFlagCallback): void {
+        const token = this.instance.config.token
+        this.instance._send_request({
+            method: 'POST',
+            url: this.instance.requestRouter.endpointFor('api', '/decide/?v=3'),
+            data: {
+                distinct_id: this.instance.get_distinct_id(),
+                token,
+            },
+            compression: this.instance.config.disable_compression ? undefined : Compression.Base64,
+            timeout: this.instance.config.feature_flag_request_timeout_ms,
+            callback: (response) => {
+                const flagPayloads = response.json?.['featureFlagPayloads']
+                callback(flagPayloads?.[key] || undefined)
+            },
+        })
+    }
+
     /*
      * See if feature flag is enabled for user.
      *

diff --git a/src/types.ts b/src/types.ts
@@ -1356,6 +1356,8 @@ export type FeatureFlagsCallback = (
     }
 ) => void
 
+export type RemoteConfigFeatureFlagCallback = (payload: JsonType) => void
+
 export interface PersistentStore {
     is_supported: () => boolean
     error: (error: any) => void