Rebrand: polkadot → pezkuwi, substrate → bizinikiwi, kusama → dicle

packages/api-derive/src/session/info.ts

@@ -0,0 +1,39 @@
+// Copyright 2017-2025 @pezkuwi/api-derive authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import type { Observable } from 'rxjs';
+import type { DeriveApi, DeriveSessionInfo } from '../types.js';
+
+import { map } from 'rxjs';
+
+import { objectSpread } from '@pezkuwi/util';
+
+import { memo } from '../util/index.js';
+
+/**
+ * @name info
+ * @description Retrieves all the session and era query and calculates specific values on it as the length of the session and eras.
+ * @example
+ * ```javascript
+ * api.derive.session.info((info) => {
+ *   console.log(`Session info ${JSON.stringify(info)}`);
+ * });
+ * ```
+ */
+export function info (instanceId: string, api: DeriveApi): () => Observable<DeriveSessionInfo> {
+  return memo(instanceId, (): Observable<DeriveSessionInfo> =>
+    api.derive.session.indexes().pipe(
+      map((indexes) => {
+        const sessionLength = api.consts?.babe?.epochDuration || api.registry.createType('u64', 1);
+        const sessionsPerEra = api.consts?.staking?.sessionsPerEra || api.registry.createType('SessionIndex', 1);
+
+        return objectSpread({
+          eraLength: api.registry.createType('BlockNumber', sessionsPerEra.mul(sessionLength)),
+          isEpoch: !!api.query.babe,
+          sessionLength,
+          sessionsPerEra
+        }, indexes);
+      })
+    )
+  );
+}