main.ts

const tasks: Array<() => Promise<number>> = [
  () => new Promise((res) => res(10)),
  () => new Promise((_, rej) => rej(new Error('Failed to fetch data'))),
  () => new Promise((res) => res(30)),
];

const executor = new SequentialPromiseExecutor(tasks);

executor.startProcessing().then((results) => {
  results.forEach((result, index) => {
    if (result.success) {
      console.log(`Task ${index} succeeded with value:`, result.value);
    } else {
      console.error(`Task ${index} failed with error:`, result.error);
    }
  });
});

SequentilaPromiseExecutor.ts

class SequentialPromiseExecutor<T> {
  constructor(private tasks: Array<() => Promise<T>>) {}

  // Async generator to yield results one by one
  async *processQueue(): AsyncGenerator<Result<T>, void, unknown> {
    for (const task of this.tasks) {
      try {
        const result = await task();
        yield { success: true, value: result };
      } catch (e) {
        yield { success: false, error: e as Error }; // Yield the original error
      }
    }
  }

  // Method to start processing and return an array of results
  async startProcessing(): Promise<Result<T>[]> {
    const results: Result<T>[] = [];
    for await (const result of this.processQueue()) {
      results.push(result);
    }
    return results;
  }
}