bknd/app/src/flows/tasks/presets/FetchTask.ts

import { Task, dynamic } from "../Task";
import { s } from "core/object/schema";

const FetchMethods = ["GET", "POST", "PUT", "PATCH", "DELETE"];

export class FetchTask<Output extends Record<string, any>> extends Task<
   typeof FetchTask.schema,
   Output
> {
   type = "fetch";

   static override schema = s.strictObject({
      url: s.string({
         pattern: "^(http|https)://",
      }),
      method: dynamic(s.string({ enum: FetchMethods, default: "GET" })).optional(),
      headers: dynamic(
         s.array(
            s.strictObject({
               key: s.string(),
               value: s.string(),
            }),
         ),
         JSON.parse,
      ).optional(),
      body: dynamic(s.string()).optional(),
      normal: dynamic(s.number(), Number.parseInt).optional(),
   });

   protected getBody(): string | undefined {
      const body = this.params.body;
      if (!body) return;
      if (typeof body === "string") return body;
      if (typeof body === "object") return JSON.stringify(body);

      throw new Error(`Invalid body type: ${typeof body}`);
   }

   async execute() {
      if (!FetchMethods.includes(this.params.method ?? "GET")) {
         throw this.error("Invalid method", {
            given: this.params.method,
            valid: FetchMethods,
         });
      }

      const body = this.getBody();
      const headers = new Headers(this.params.headers?.map((h) => [h.key, h.value]));

      const result = await fetch(this.params.url, {
         method: this.params.method ?? "GET",
         headers,
         body,
      });

      if (!result.ok) {
         throw this.error("Failed to fetch", {
            status: result.status,
            statusText: result.statusText,
         });
      }

      const data = (await result.json()) as Output;
      return data;
   }
}