Simplify types and fix intelligence

Author: zyc9012

mod.ts

@@ -13,7 +13,6 @@ export type {
   AllowArbitraryParams,
   BaseParameters,
   BaseResponse,
-  EngineName,
   EngineParameters,
   GetBySearchIdParameters,
   Location,

src/serpapi.ts

@@ -1,10 +1,9 @@
+import { EngineMap } from "./engines/engine_map.ts";
 import { InvalidArgumentTypesError } from "./errors.ts";
 import {
   AccountApiParameters,
   AccountInformation,
-  AllowArbitraryParams,
   BaseResponse,
-  EngineName,
   EngineParameters,
   GetBySearchIdParameters,
   Locations,
@@ -71,16 +70,16 @@ const SEARCH_ARCHIVE_PATH = `/searches`;
  * });
  */
 export function getJson<
-  E extends EngineName = EngineName,
-  P1 extends AllowArbitraryParams<EngineParameters<E>> = EngineParameters<E>,
-  P2 extends AllowArbitraryParams<EngineParameters<E, false>> =
-    EngineParameters<E, false>,
+  E extends keyof EngineMap,
 >(
   ...args:
-    | [parameters: P1, callback?: (json: BaseResponse<E>) => void]
     | [
-      engine: string, // intentionally kept as a string to support arbitrary params
-      parameters: P2,
+      parameters: EngineParameters<E>,
+      callback?: (json: BaseResponse<E>) => void,
+    ]
+    | [
+      engine: E | string,
+      parameters: EngineParameters<E, false>,
       callback?: (json: BaseResponse<E>) => void,
     ]
 ): Promise<BaseResponse<E>> {
@@ -89,7 +88,7 @@ export function getJson<
     typeof args[1] === "object"
   ) {
     const [engine, parameters, callback] = args;
-    const newParameters = { engine, ...parameters } as P1;
+    const newParameters = { ...parameters, engine } as EngineParameters<E>;
     return _getJson(newParameters, callback);
   } else if (
     typeof args[0] === "object" &&
@@ -103,10 +102,9 @@ export function getJson<
 }
 
 async function _getJson<
-  E extends EngineName = EngineName,
-  P extends AllowArbitraryParams<EngineParameters<E>> = EngineParameters<E>,
+  E extends keyof EngineMap,
 >(
-  parameters: P,
+  parameters: EngineParameters<E>,
   callback?: (json: BaseResponse<E>) => void,
 ): Promise<BaseResponse<E>> {
   const key = validateApiKey(parameters.api_key, true);
@@ -156,16 +154,16 @@ async function _getJson<
  * getHtml({ engine: "google", api_key: API_KEY, q: "coffee" }, console.log);
  */
 export function getHtml<
-  E extends EngineName = EngineName,
-  P1 extends AllowArbitraryParams<EngineParameters<E>> = EngineParameters<E>,
-  P2 extends AllowArbitraryParams<EngineParameters<E, false>> =
-    EngineParameters<E, false>,
+  E extends keyof EngineMap,
 >(
   ...args:
-    | [parameters: P1, callback?: (html: string) => void]
     | [
-      engine: string, // intentionally kept as a string to support arbitrary params
-      parameters: P2,
+      parameters: EngineParameters<E>,
+      callback?: (html: string) => void,
+    ]
+    | [
+      engine: E | string,
+      parameters: EngineParameters<E, false>,
       callback?: (html: string) => void,
     ]
 ): Promise<string> {
@@ -174,7 +172,7 @@ export function getHtml<
     typeof args[1] === "object"
   ) {
     const [engine, parameters, callback] = args;
-    const newParameters = { engine, ...parameters } as P1;
+    const newParameters = { ...parameters, engine } as EngineParameters<E>;
     return _getHtml(newParameters, callback);
   } else if (
     typeof args[0] === "object" &&
@@ -188,10 +186,9 @@ export function getHtml<
 }
 
 async function _getHtml<
-  E extends EngineName = EngineName,
-  P extends AllowArbitraryParams<EngineParameters<E>> = EngineParameters<E>,
+  E extends keyof EngineMap,
 >(
-  parameters: P,
+  parameters: EngineParameters<E>,
   callback?: (html: string) => void,
 ): Promise<string> {
   const key = validateApiKey(parameters.api_key, true);
@@ -233,7 +230,7 @@ async function _getHtml<
  * getJsonBySearchId(id, { api_key: API_KEY }, console.log);
  */
 export async function getJsonBySearchId<
-  R extends BaseResponse,
+  R extends BaseResponse<keyof EngineMap>,
 >(
   searchId: string,
   parameters: GetBySearchIdParameters = {},

src/types.ts

@@ -47,20 +47,19 @@ export type BaseParameters = {
   timeout?: number;
 };
 
-// https://github.com/microsoft/TypeScript/issues/29729
-// deno-lint-ignore ban-types
-type AnyEngineName = string & {};
-export type EngineName = (keyof EngineMap) | AnyEngineName;
 export type EngineParameters<
-  E extends EngineName = EngineName,
-  W = true, // flag for whether `engine` is a required param
-> = {
-  [K in E]:
-    & (W extends true ? { engine: K } : { engine?: K })
-    & (K extends keyof EngineMap ? EngineMap[K]["parameters"] : BaseParameters);
-}[E];
+  E extends keyof EngineMap,
+  EngineRequired = true,
+> =
+  // https://github.com/microsoft/TypeScript/issues/29729
+  // deno-lint-ignore ban-types
+  & (EngineRequired extends true ? { engine: E | (string & {}) }
+    // deno-lint-ignore ban-types
+    : { engine?: E | (string & {}) })
+  & EngineMap[E]["parameters"]
+  & Record<string, unknown>;
 
-export type BaseResponse<E extends EngineName = EngineName> = {
+export type BaseResponse<E extends keyof EngineMap> = {
   search_metadata: {
     id: string;
     status: "Queued" | "Processing" | "Success";

src/utils.ts

@@ -1,5 +1,6 @@
-import type { EngineName, EngineParameters } from "./types.ts";
+import type { EngineParameters } from "./types.ts";
 import { version } from "../version.ts";
+import { EngineMap } from "./engines/engine_map.ts";
 
 type UrlParameters = Record<
   string,
@@ -35,15 +36,15 @@ function getBaseUrl() {
   return "https://serpapi.com";
 }
 
-type NextParameters<E extends EngineName = EngineName> = {
+type NextParameters<E extends keyof EngineMap> = {
   [
     K in keyof Omit<
       EngineParameters<E>,
       "api_key" | "no_cache" | "async" | "timeout"
     >
   ]: string;
 };
-export function extractNextParameters<E extends EngineName = EngineName>(json: {
+export function extractNextParameters<E extends keyof EngineMap>(json: {
   serpapi_pagination?: { next: string };
   pagination?: { next: string };
 }) {