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Guide
Examples
API Reference
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byethrow
@praha/byethrow

Modules

Result

Types

Type Alias: Failure<E>
Type Alias: InferFailure<T>
Type Alias: InferSuccess<T>
Type Alias: Result<T, E>
Type Alias: ResultAsync<T, E>
Type Alias: ResultFor<R, T, E>
Type Alias: ResultMaybeAsync<T, E>
Type Alias: Success<T>

Functions

Function: andThen()
Function: andThrough()
Function: assertFailure()
Function: assertSuccess()
Function: bind()
Function: combine()
Function: do()
Function: fail()
Function: inspect()
Function: inspectError()
Function: isFailure()
Function: isResult()
Function: isSuccess()
Function: map()
Function: mapError()
Function: orElse()
Function: parse()
Function: pipe()
Function: succeed()
Function: try()
Function: unwrap()
Function: unwrapError()

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#Function: inspect()

Executes a side effect function on the success value of a Result or ResultAsync, without modifying the original result. This is useful for debugging, logging, or performing other side effects while maintaining the original value and error state.

#Type Param

The input Result or ResultAsync.

#Type Param

The return type of the inspection function.

#Examples

import { 
import Result
Result
} from '@praha/byethrow';
const
const result: Result.Result<number, never>
result
=
import Result
Result
.
const pipe: <Result.Result<number, never>, Result.Result<number, never>>(a: Result.Result<number, never>, ab: (a: Result.Result<number, never>) => Result.Result<number, never>) => Result.Result<number, never> (+25 overloads)
pipe
(
import Result
Result
.
const succeed: <number>(value: number) => Result.Result<number, never> (+1 overload)
succeed
(42),
import Result
Result
.
const inspect: <Result.Result<number, never>, void>(fn: (a: number) => void) => (result: Result.Result<number, never>) => Result.Result<number, never> (+1 overload)
inspect
((
value: number
value
) =>
var console: Console

The console module provides a simple debugging console that is similar to the JavaScript console mechanism provided by web browsers.

The module exports two specific components:

  • A Console class with methods such as console.log(), console.error() and console.warn() that can be used to write to any Node.js stream.
  • A global console instance configured to write to process.stdout and process.stderr. The global console can be used without importing the node:console module.

Warning: The global console object's methods are neither consistently synchronous like the browser APIs they resemble, nor are they consistently asynchronous like all other Node.js streams. See the note on process I/O for more information.

Example using the global console:

console.log('hello world');
// Prints: hello world, to stdout
console.log('hello %s', 'world');
// Prints: hello world, to stdout
console.error(new Error('Whoops, something bad happened'));
// Prints error message and stack trace to stderr:
//   Error: Whoops, something bad happened
//     at [eval]:5:15
//     at Script.runInThisContext (node:vm:132:18)
//     at Object.runInThisContext (node:vm:309:38)
//     at node:internal/process/execution:77:19
//     at [eval]-wrapper:6:22
//     at evalScript (node:internal/process/execution:76:60)
//     at node:internal/main/eval_string:23:3

const name = 'Will Robinson';
console.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to stderr

Example using the Console class:

const out = getStreamSomehow();
const err = getStreamSomehow();
const myConsole = new console.Console(out, err);

myConsole.log('hello world');
// Prints: hello world, to out
myConsole.log('hello %s', 'world');
// Prints: hello world, to out
myConsole.error(new Error('Whoops, something bad happened'));
// Prints: [Error: Whoops, something bad happened], to err

const name = 'Will Robinson';
myConsole.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to err
@seesource
console
.
Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)

Prints to stdout with newline. Multiple arguments can be passed, with the first used as the primary message and all additional used as substitution values similar to printf(3) (the arguments are all passed to util.format()).

const count = 5;
console.log('count: %d', count);
// Prints: count: 5, to stdout
console.log('count:', count);
// Prints: count: 5, to stdout

See util.format() for more information.

@sincev0 .1.100
log
('Debug:',
value: number
value
)),
); // Console output: "Debug: 42" // Result: { type: 'Success', value: 42 }
import { 
import Result
Result
} from '@praha/byethrow';
const
const result: Result.Result<never, string>
result
=
import Result
Result
.
const pipe: <Result.Result<never, string>, Result.Result<never, string>>(a: Result.Result<never, string>, ab: (a: Result.Result<never, string>) => Result.Result<never, string>) => Result.Result<never, string> (+25 overloads)
pipe
(
import Result
Result
.
const fail: <string>(error: string) => Result.Result<never, string> (+1 overload)
fail
('error'),
import Result
Result
.
const inspect: <Result.Result<never, string>, void>(fn: (a: never) => void) => (result: Result.Result<never, string>) => Result.Result<never, string> (+1 overload)
inspect
((
value: never
value
) =>
var console: Console

The console module provides a simple debugging console that is similar to the JavaScript console mechanism provided by web browsers.

The module exports two specific components:

  • A Console class with methods such as console.log(), console.error() and console.warn() that can be used to write to any Node.js stream.
  • A global console instance configured to write to process.stdout and process.stderr. The global console can be used without importing the node:console module.

Warning: The global console object's methods are neither consistently synchronous like the browser APIs they resemble, nor are they consistently asynchronous like all other Node.js streams. See the note on process I/O for more information.

Example using the global console:

console.log('hello world');
// Prints: hello world, to stdout
console.log('hello %s', 'world');
// Prints: hello world, to stdout
console.error(new Error('Whoops, something bad happened'));
// Prints error message and stack trace to stderr:
//   Error: Whoops, something bad happened
//     at [eval]:5:15
//     at Script.runInThisContext (node:vm:132:18)
//     at Object.runInThisContext (node:vm:309:38)
//     at node:internal/process/execution:77:19
//     at [eval]-wrapper:6:22
//     at evalScript (node:internal/process/execution:76:60)
//     at node:internal/main/eval_string:23:3

const name = 'Will Robinson';
console.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to stderr

Example using the Console class:

const out = getStreamSomehow();
const err = getStreamSomehow();
const myConsole = new console.Console(out, err);

myConsole.log('hello world');
// Prints: hello world, to out
myConsole.log('hello %s', 'world');
// Prints: hello world, to out
myConsole.error(new Error('Whoops, something bad happened'));
// Prints: [Error: Whoops, something bad happened], to err

const name = 'Will Robinson';
myConsole.warn(`Danger ${name}! Danger!`);
// Prints: Danger Will Robinson! Danger!, to err
@seesource
console
.
Console.log(message?: any, ...optionalParams: any[]): void (+1 overload)

Prints to stdout with newline. Multiple arguments can be passed, with the first used as the primary message and all additional used as substitution values similar to printf(3) (the arguments are all passed to util.format()).

const count = 5;
console.log('count: %d', count);
// Prints: count: 5, to stdout
console.log('count:', count);
// Prints: count: 5, to stdout

See util.format() for more information.

@sincev0 .1.100
log
('Debug:',
value: never
value
)),
); // No console output // Result: { type: 'Failure', error: 'error' }

#See

pipe - It is recommended to use this function with the pipe function for better readability and composability.

#Call Signature

inspect<R1, R2>(fn): (result) => ResultFor<R1 | R2, InferSuccess<R1>, InferFailure<R1>>

Defined in: functions/inspect.ts:46

#Type Parameters

#R1

R1 extends ResultMaybeAsync<any, any>

#R2

R2

#Parameters

#fn

(a) => R2

#Returns

(result): ResultFor<R1 | R2, InferSuccess<R1>, InferFailure<R1>>

#Parameters

#result

R1

#Returns

ResultFor<R1 | R2, InferSuccess<R1>, InferFailure<R1>>

#Call Signature

inspect<F>(fn): <R1>(result) => ResultFor<R1 | ReturnType<F>, InferSuccess<R1>, InferFailure<R1>>

Defined in: functions/inspect.ts:47

#Type Parameters

#F

F extends (a) => unknown

#Parameters

#fn

F

#Returns

<R1>(result): ResultFor<R1 | ReturnType<F>, InferSuccess<R1>, InferFailure<R1>>

#Type Parameters

#R1

R1 extends ResultMaybeAsync<Parameters<F>[0], any>

#Parameters

#result

R1

#Returns

ResultFor<R1 | ReturnType<F>, InferSuccess<R1>, InferFailure<R1>>