Concerns Over Handling Errors in Generators and Resulting Types

export function generateSummary({ aggregate, data, property }: GenerateSummaryArgs) {
  // Effect<Value, NoSuchElementException, never>
  const result = Effect.gen(function* ($) {
    const summary = yield* $(
      ReadonlyRecord.get(propertyMap, property),
      Effect.tapError(Console.warn),
      Effect.option,
    );

    if (Option.isNone(summary)) {
      return {
        content: "An error has occured. The metric data you've requested does not exist.",
        title: "Metric Comparison",
      };
    }

    const comparative = yield* $(
      data.percentageChange,
      Effect.fromNullable,
      Effect.map((value) => (value <= 0 ? `${Math.abs(value)}% less` : `${Math.abs(value)}% more`)),
      Effect.option,
    );

    if (Option.isNone(comparative)) {
      return yield *$(summary, Effect.map(({title}) => ({
        content: "There is not enough data available to present this comparison.",
        title,
      })));
    }

    return yield* $(
      Effect.all({ summary, comparative }),
      Effect.map((result) => ({
        title: result.summary.title,
        content: [
          `You have ${result.summary.adjective}`,
          `${result.comparative} ${result.summary.pluralUnit}`,
          `today than this time last ${aggregate.toString()}.`,
        ].join(" "),
      })),
    );
  });

  return result.pipe(Effect.runSync)
}

export function generateSummary({ aggregate, data, property }: GenerateSummaryArgs) {
  // Effect<Value, NoSuchElementException, never>
  const result = Effect.gen(function* ($) {
    const summary = yield* $(
      ReadonlyRecord.get(propertyMap, property),
      Effect.tapError(Console.warn),
      Effect.option,
    );

    if (Option.isNone(summary)) {
      return {
        content: "An error has occured. The metric data you've requested does not exist.",
        title: "Metric Comparison",
      };
    }

    const comparative = yield* $(
      data.percentageChange,
      Effect.fromNullable,
      Effect.map((value) => (value <= 0 ? `${Math.abs(value)}% less` : `${Math.abs(value)}% more`)),
      Effect.option,
    );

    if (Option.isNone(comparative)) {
      return yield *$(summary, Effect.map(({title}) => ({
        content: "There is not enough data available to present this comparison.",
        title,
      })));
    }

    return yield* $(
      Effect.all({ summary, comparative }),
      Effect.map((result) => ({
        title: result.summary.title,
        content: [
          `You have ${result.summary.adjective}`,
          `${result.comparative} ${result.summary.pluralUnit}`,
          `today than this time last ${aggregate.toString()}.`,
        ].join(" "),
      })),
    );
  });

  return result.pipe(Effect.runSync)
}