Add mempool endpoint

src/stacks-api/index.ts

@@ -19,11 +19,15 @@ export type * as StackingPool from "./stacking-pool/index.js";
 import { transactions } from "./transactions/index.js";
 export type * as Transactions from "./transactions/index.js";
 
+import { mempool } from "./mempool/index.js";
+export type * as Mempool from "./mempool/index.js";
+
 export const stacksApi = {
   accounts,
   blocks,
   faucets,
   info,
+  mempool,
   proofOfTransfer,
   stackingPool,
   transactions,

src/stacks-api/mempool/index.ts

@@ -0,0 +1,6 @@
+import { transactionFeePriorities } from "./transaction-fee-priorities.js";
+export type * as TransactionFeePriorities from "./transaction-fee-priorities.js";
+
+export const mempool = {
+  transactionFeePriorities,
+};

src/stacks-api/mempool/transaction-fee-priorities.ts

@@ -0,0 +1,79 @@
+import {
+  error,
+  safePromise,
+  success,
+  type Result,
+  type SafeError,
+} from "../../utils/safe.js";
+import type { ApiRequestOptions } from "../types.js";
+
+export type FeePrioritiesResponse = {
+  all: {
+    no_priority: number;
+    low_priority: number;
+    medium_priority: number;
+    high_priority: number;
+  };
+  token_transfer: {
+    no_priority: number;
+    low_priority: number;
+    medium_priority: number;
+    high_priority: number;
+  };
+  smart_contract: {
+    no_priority: number;
+    low_priority: number;
+    medium_priority: number;
+    high_priority: number;
+  };
+  contract_call: {
+    no_priority: number;
+    low_priority: number;
+    medium_priority: number;
+    high_priority: number;
+  };
+};
+
+export async function transactionFeePriorities(
+  opts: ApiRequestOptions,
+): Promise<
+  Result<
+    FeePrioritiesResponse,
+    SafeError<
+      "FetchFeePrioritiesError" | "ParseBodyError" | "ValidateDataError"
+    >
+  >
+> {
+  const init: RequestInit = {};
+  if (opts.apiKeyConfig) {
+    init.headers = {
+      [opts.apiKeyConfig.header]: opts.apiKeyConfig.key,
+    };
+  }
+
+  const endpoint = `${opts.baseUrl}/extended/v2/mempool/fees`;
+  const res = await fetch(endpoint, init);
+
+  if (!res.ok) {
+    return error({
+      name: "FetchFeePrioritiesError",
+      message: "Failed to fetch transaction fee priorities.",
+      data: {
+        status: res.status,
+        statusText: res.statusText,
+        bodyParseResult: await safePromise(res.text()),
+      },
+    });
+  }
+
+  const [jsonError, data] = await safePromise(res.json());
+  if (jsonError) {
+    return error({
+      name: "ParseBodyError",
+      message: "Failed to parse response body as JSON.",
+      data: jsonError,
+    });
+  }
+
+  return success(data as FeePrioritiesResponse);
+}