Function createFetchTask

packages/zone.js/lib/common/fetch.ts:35–91

(
      source: string,
      data: TaskData | undefined,
      originalImpl: any,
      self: any,
      args: any[],
      ac?: AbortController,
    )

    const placeholder = function () {};

    const createFetchTask = (
      source: string,
      data: TaskData | undefined,
      originalImpl: any,
      self: any,
      args: any[],
      ac?: AbortController,
    ) =>
      new Promise((resolve, reject) => {
        const task = Zone.current.scheduleMacroTask(
          source,
          placeholder,
          data,
          () => {
            // The promise object returned by the original implementation passed into the
            // function. This might be a `fetch` promise, `Response.prototype.json` promise,
            // etc.
            let implPromise;
            let zone = Zone.current;

            try {
              (zone as any)[fetchTaskScheduling] = true;
              implPromise = originalImpl.apply(self, args);
            } catch (error) {
              reject(error);
              return;
            } finally {
              (zone as any)[fetchTaskScheduling] = false;
            }

            if (!(implPromise instanceof ZoneAwarePromise)) {
              let ctor = implPromise.constructor;
              if (!ctor[symbolThenPatched]) {
                api.patchThen(ctor);
              }
            }

            implPromise.then(
              (resource: any) => {
                if (task.state !== 'notScheduled') {
                  task.invoke();
                }
                resolve(resource);
              },
              (error: any) => {
                if (task.state !== 'notScheduled') {
                  task.invoke();
                }
                reject(error);
              },
            );
          },
          () => {
            ac?.abort();
          },
        );
      });