Add extractNextParameters util

Author: sebastianquek

src/types.ts

@@ -52,6 +52,8 @@ export type BaseResponse<P = Record<string | number | symbol, never>> = {
   search_parameters:
     & { engine: string }
     & Omit<BaseParameters & P, "api_key" | "no_cache" | "async" | "timeout">;
+  serpapi_pagination?: { next: string };
+  pagination?: { next: string };
   // deno-lint-ignore no-explicit-any
   [key: string]: any; // TODO(seb): use recursive type
 };

src/utils.ts

@@ -1,3 +1,4 @@
+import type { EngineMap } from "./engines/engine_map.ts";
 import { version } from "../version.ts";
 
 type UrlParameters = Record<
@@ -34,6 +35,30 @@ function getBaseUrl() {
   return "https://serpapi.com";
 }
 
+type NextParametersKeys<E extends keyof EngineMap> = Omit<
+  EngineMap[E]["parameters"],
+  "api_key" | "no_cache" | "async" | "timeout"
+>;
+type NextParameters<E extends keyof EngineMap> = {
+  [K in keyof NextParametersKeys<E>]: string;
+};
+export function extractNextParameters<
+  E extends keyof EngineMap,
+>(json: {
+  serpapi_pagination?: { next: string };
+  pagination?: { next: string };
+}) {
+  const nextUrlString = json["serpapi_pagination"]?.["next"] ||
+    json["pagination"]?.["next"];
+
+  if (nextUrlString) {
+    const nextUrl = new URL(nextUrlString);
+    const nextParameters = Object.fromEntries(nextUrl.searchParams.entries());
+    delete nextParameters["engine"];
+    return nextParameters as NextParameters<E>;
+  }
+}
+
 function getSource() {
   const moduleSource = `serpapi@${version}`;
   try {

tests/utils_test.ts

@@ -16,13 +16,58 @@ import {
   assertMatch,
   assertRejects,
 } from "https://deno.land/std@0.170.0/testing/asserts.ts";
-import { _internals, buildUrl, execute } from "../src/utils.ts";
+import {
+  _internals,
+  buildUrl,
+  execute,
+  extractNextParameters,
+} from "../src/utils.ts";
 
 loadSync({ export: true });
 const BASE_URL = Deno.env.get("ENV_TYPE") === "local"
   ? "http://localhost:3000"
   : "https://serpapi.com";
 
+describe("extractNextParameters", () => {
+  it("with serpapi_pagination property", () => {
+    assertEquals(
+      extractNextParameters<"google">({
+        serpapi_pagination: {
+          next:
+            "https://serpapi.com/search.json?device=desktop&engine=google&gl=us&google_domain=google.com&hl=en&location=Austin%2C+Texas%2C+United+States&q=coffee&start=10",
+        },
+      }),
+      {
+        device: "desktop",
+        gl: "us",
+        google_domain: "google.com",
+        hl: "en",
+        location: "Austin, Texas, United States",
+        q: "coffee",
+        start: "10",
+      },
+    );
+  });
+
+  it("with pagination property", () => {
+    assertEquals(
+      extractNextParameters<"google_scholar_profiles">(
+        {
+          pagination: {
+            next:
+              "https://serpapi.com/search.json?after_author=rZlDAYoq__8J&engine=google_scholar_profiles&hl=en&mauthors=Mike",
+          },
+        },
+      ),
+      {
+        after_author: "rZlDAYoq__8J",
+        hl: "en",
+        mauthors: "Mike",
+      },
+    );
+  });
+});
+
 describe("buildUrl", () => {
   let urlStub: Stub;