try-catch

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tryCatchR

In try-catch, which is standard for JavaScript, it is not possible to define a return value inside try. This inevitably leads to declaring mutable variables outside of try-catch, which cannot be set immutably.

tryCatchR acts as a function that encapsulates try-catch as a function that returns a return value so that it can be treated immutably.

interface DataSomething {
  something1: string;
  something2: string;
}
interface Result {
  data: DataSomething | undefined;
  errors: string[];
}

// try-catch syntax makes apiResult mutable
let apiResult: Result;
try {
  const data = await fetchFuncSometimesError();
  apiResult = {
    data,
    errors: [],
  };
} catch(error) {
  apiResult = {
    data: undefined,
    errors: [String(error)],
  };
}

// tryCatchR realizes apiResult2 as immutable
import { tryCatchR } from "@y-walter/typescript-utils";

const apiResult2 = tryCatchR(() => {
  const data = await fetchFuncSometimesError();
  return {
    data,
    errors: [],
  }
}, {
  onError: (error) => {
    return {
      data: undefined,
      errors: [String(error)],
    }
  }
});

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