byethrow
  • 日本語

      • Result をデバッグする

      複雑なパイプラインをデバッグする際、各ステップで何が起こっているかを確認する必要があります。 inspect と inspectError 関数を使うと、フローに影響を与えずに値を確認できます。

      inspect - 成功値の確認

      inspect は成功値に対して副作用関数を実行しますが、常に元の結果を変更せずに返します。

      import { 
      import Result
      Result       } from '@praha/byethrow';      

const 
      const result: Result.Result<number, never>
      result       = 
      import Result
      Result      .
      const pipe: <Result.Result<42, never>, Result.Result<42, never>, Result.Result<number, never>>(a: Result.Result<42, never>, ab: (a: Result.Result<42, never>) => Result.Result<42, never>, bc: (b: Result.Result<42, never>) => Result.Result<number, never>) => Result.Result<number, never> (+25 overloads)
      pipe      (      
  
      import Result
      Result      .
      const succeed: <42>(value: 42) => Result.Result<42, never> (+1 overload)
      succeed      (42),      
  
      import Result
      Result      .
      const inspect: <Result.Result<42, never>, void>(fn: (a: 42) => void) => (result: Result.Result<42, never>) => Result.Result<42, never> (+1 overload)
      inspect      ((
      value: 42
      value      ) => 
      var console: Console
      console      .
      Console.log(...data: any[]): void
      The console.log() static method outputs a message to the console.
      

      MDN Reference
      log      ('Value:', 
      value: 42
      value      )),      
  
      import Result
      Result      .
      const map: <Result.Result<42, never>, number>(fn: (a: 42) => number) => (result: Result.Result<42, never>) => Result.Result<number, never> (+1 overload)
      map      ((
      x: 42
      x      ) => 
      x: 42
      x       * 2),      
);
// コンソール: "Value: 42"
// { type: 'Success', value: 84 }

      失敗時、inspect は何もしません。

      import { 
      import Result
      Result       } from '@praha/byethrow';      

const 
      const result: Result.Result<never, "error">
      result       = 
      import Result
      Result      .
      const pipe: <Result.Result<never, "error">, Result.Result<never, "error">>(a: Result.Result<never, "error">, ab: (a: Result.Result<never, "error">) => Result.Result<never, "error">) => Result.Result<never, "error"> (+25 overloads)
      pipe      (      
  
      import Result
      Result      .
      const fail: <"error">(error: "error") => Result.Result<never, "error"> (+1 overload)
      fail      ('error'),      
  
      import Result
      Result      .
      const inspect: <Result.Result<never, "error">, void>(fn: (a: never) => void) => (result: Result.Result<never, "error">) => Result.Result<never, "error"> (+1 overload)
      inspect      ((
      value: never
      value      ) => 
      var console: Console
      console      .
      Console.log(...data: any[]): void
      The console.log() static method outputs a message to the console.
      

      MDN Reference
      log      ('Value:', 
      value: never
      value      )), // 呼ばれない      
);
// { type: 'Failure', error: 'error' }

      inspectError - 失敗値の確認

      inspectError は失敗値に対して副作用関数を実行しますが、常に元の結果を変更せずに返します。

      import { 
      import Result
      Result       } from '@praha/byethrow';      

const 
      const result: Result.Result<never, "Something went wrong">
      result       = 
      import Result
      Result      .
      const pipe: <Result.Result<never, "Something went wrong">, Result.Result<never, "Something went wrong">>(a: Result.Result<never, "Something went wrong">, ab: (a: Result.Result<never, "Something went wrong">) => Result.Result<never, "Something went wrong">) => Result.Result<never, "Something went wrong"> (+25 overloads)
      pipe      (      
  
      import Result
      Result      .
      const fail: <"Something went wrong">(error: "Something went wrong") => Result.Result<never, "Something went wrong"> (+1 overload)
      fail      ('Something went wrong'),      
  
      import Result
      Result      .
      const inspectError: <Result.Result<never, "Something went wrong">, void>(fn: (a: "Something went wrong") => void) => (result: Result.Result<never, "Something went wrong">) => Result.Result<never, "Something went wrong"> (+1 overload)
      inspectError      ((
      error: "Something went wrong"
      error      ) => 
      var console: Console
      console      .
      Console.error(...data: any[]): void
      The console.error() static method outputs a message to the console at the "error" log level. The message is only displayed to the user if the console is configured to display error output. In most cases, the log level is configured within the console UI. The message may be formatted as an error, with red colors and call stack information.
      

      MDN Reference
      error      ('Error:', 
      error: "Something went wrong"
      error      )),      
);
// コンソール: "Error: Something went wrong"
// { type: 'Failure', error: 'Something went wrong' }

      成功時、inspectError は何もしません。

      import { 
      import Result
      Result       } from '@praha/byethrow';      

const 
      const result: Result.Result<42, never>
      result       = 
      import Result
      Result      .
      const pipe: <Result.Result<42, never>, Result.Result<42, never>>(a: Result.Result<42, never>, ab: (a: Result.Result<42, never>) => Result.Result<42, never>) => Result.Result<42, never> (+25 overloads)
      pipe      (      
  
      import Result
      Result      .
      const succeed: <42>(value: 42) => Result.Result<42, never> (+1 overload)
      succeed      (42),      
  
      import Result
      Result      .
      const inspectError: <Result.Result<42, never>, void>(fn: (a: never) => void) => (result: Result.Result<42, never>) => Result.Result<42, never> (+1 overload)
      inspectError      ((
      error: never
      error      ) => 
      var console: Console
      console      .
      Console.error(...data: any[]): void
      The console.error() static method outputs a message to the console at the "error" log level. The message is only displayed to the user if the console is configured to display error output. In most cases, the log level is configured within the console UI. The message may be formatted as an error, with red colors and call stack information.
      

      MDN Reference
      error      ('Error:', 
      error: never
      error      )), // 呼ばれない      
);
// { type: 'Success', value: 42 }

      例：パイプラインのトレース

      import { 
      import Result
      Result       } from '@praha/byethrow';      

const 
      const processData: (input: Input) => Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed">
      processData       = (
      input: Input
      input      : 
      type Input = {
    data: string;
}
      Input      ) => {      
  return 
      import Result
      Result      .
      const pipe: <Result.Result<Input, never>, Result.Result<Input, never>, Result.Result<Input, "ValidateFailed">, Result.Result<Input, "ValidateFailed">, Result.Result<Transformed, "ValidateFailed" | "TransformFailed">, Result.Result<Transformed, "ValidateFailed" | "TransformFailed">, Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed">, Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed">, Result.Result<...>>(a: Result.Result<...>, ab: (a: Result.Result<...>) => Result.Result<...>, bc: (b: Result.Result<...>) => Result.Result<...>, cd: (c: Result.Result<...>) => Result.Result<...>, de: (d: Result.Result<...>) => Result.Result<...>, ef: (e: Result.Result<...>) => Result.Result<...>, fg: (f: Result.Result<...>) => Result.Result<...>, gh: (g: Result.Result<...>) => Result.Result<...>, hi: (h: Result.Result<...>) => Result.Result<...>) => Result.Result<...> (+25 overloads)
      pipe      (      
    
      import Result
      Result      .
      const succeed: <Input>(value: Input) => Result.Result<Input, never> (+1 overload)
      succeed      (
      input: Input
      input      ),      
    
      import Result
      Result      .
      const inspect: <Result.Result<Input, never>, void>(fn: (a: Input) => void) => (result: Result.Result<Input, never>) => Result.Result<Input, never> (+1 overload)
      inspect      ((
      value: Input
      value      ) => 
      var console: Console
      console      .
      Console.log(...data: any[]): void
      The console.log() static method outputs a message to the console.
      

      MDN Reference
      log      ('Input:', 
      value: Input
      value      )),      
    
      import Result
      Result      .
      const andThrough: <Result.Result<Input, never>, Result.Result<Input, "ValidateFailed">>(fn: (a: Input) => Result.Result<Input, "ValidateFailed">) => (result: Result.Result<Input, never>) => Result.Result<Input, "ValidateFailed"> (+1 overload)
      andThrough      (
      const validate: (input: Input) => Result.Result<Input, "ValidateFailed">
      validate      ),      
    
      import Result
      Result      .
      const inspect: <Result.Result<Input, "ValidateFailed">, void>(fn: (a: Input) => void) => (result: Result.Result<Input, "ValidateFailed">) => Result.Result<Input, "ValidateFailed"> (+1 overload)
      inspect      ((
      value: Input
      value      ) => 
      var console: Console
      console      .
      Console.log(...data: any[]): void
      The console.log() static method outputs a message to the console.
      

      MDN Reference
      log      ('After validation:', 
      value: Input
      value      )),      
    
      import Result
      Result      .
      const andThen: <Result.Result<Input, "ValidateFailed">, Result.Result<Transformed, "TransformFailed">>(fn: (a: Input) => Result.Result<Transformed, "TransformFailed">) => (result: Result.Result<Input, "ValidateFailed">) => Result.Result<Transformed, "ValidateFailed" | "TransformFailed"> (+1 overload)
      andThen      (
      const transform: (input: Input) => Result.Result<Transformed, "TransformFailed">
      transform      ),      
    
      import Result
      Result      .
      const inspect: <Result.Result<Transformed, "ValidateFailed" | "TransformFailed">, void>(fn: (a: Transformed) => void) => (result: Result.Result<Transformed, "ValidateFailed" | "TransformFailed">) => Result.Result<Transformed, "ValidateFailed" | "TransformFailed"> (+1 overload)
      inspect      ((
      value: Transformed
      value      ) => 
      var console: Console
      console      .
      Console.log(...data: any[]): void
      The console.log() static method outputs a message to the console.
      

      MDN Reference
      log      ('After transform:', 
      value: Transformed
      value      )),      
    
      import Result
      Result      .
      const andThen: <Result.Result<Transformed, "ValidateFailed" | "TransformFailed">, Result.Result<Saved, "SaveFailed">>(fn: (a: Transformed) => Result.Result<Saved, "SaveFailed">) => (result: Result.Result<Transformed, "ValidateFailed" | "TransformFailed">) => Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed"> (+1 overload)
      andThen      (
      const save: (input: Transformed) => Result.Result<Saved, "SaveFailed">
      save      ),      
    
      import Result
      Result      .
      const inspect: <Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed">, void>(fn: (a: Saved) => void) => (result: Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed">) => Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed"> (+1 overload)
      inspect      ((
      value: Saved
      value      ) => 
      var console: Console
      console      .
      Console.log(...data: any[]): void
      The console.log() static method outputs a message to the console.
      

      MDN Reference
      log      ('After save:', 
      value: Saved
      value      )),      
    
      import Result
      Result      .
      const inspectError: <Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed">, void>(fn: (a: "ValidateFailed" | "TransformFailed" | "SaveFailed") => void) => (result: Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed">) => Result.Result<Saved, "ValidateFailed" | "TransformFailed" | "SaveFailed"> (+1 overload)
      inspectError      ((
      error: "ValidateFailed" | "TransformFailed" | "SaveFailed"
      error      ) => 
      var console: Console
      console      .
      Console.error(...data: any[]): void
      The console.error() static method outputs a message to the console at the "error" log level. The message is only displayed to the user if the console is configured to display error output. In most cases, the log level is configured within the console UI. The message may be formatted as an error, with red colors and call stack information.
      

      MDN Reference
      error      ('Pipeline failed:', 
      error: "ValidateFailed" | "TransformFailed" | "SaveFailed"
      error      )),      
  );
};

      リファレンス

      関数目的
      inspect(fn)成功値に対して副作用を実行する
      inspectError(fn)エラー値に対して副作用を実行する