#Result

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

const 
const validateId: (id: string) => Result.Failure<Error> | Result.Success<void>validateId = (
id: stringid: string) => {
  if (!
id: stringid.
String.startsWith(searchString: string, position?: number): boolean
Returns true if the sequence of elements of searchString converted to a String is the
same as the corresponding elements of this object (converted to a String) starting at
position. Otherwise returns false.startsWith('u')) {
    return 
import ResultResult.
const fail: <Error>(error: Error) => Result.Result<never, Error> (+1 overload)fail(new 
var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)
Error('Invalid ID format'));
  }
  return 
import ResultResult.
const succeed: () => Result.ResultFor<never, void, never> (+1 overload)succeed();
};

const 
const findUser: (id: string) => Result.Result<{
    id: string;
    name: string;
}, Error>
findUser = 
import ResultResult.
try<(id: string) => {
    id: string;
    name: string;
}, Error>(options: {
    try: (id: string) => {
        id: string;
        name: string;
    };
    catch: (error: unknown) => Error;
}): (id: string) => Result.Result<{
    id: string;
    name: string;
}, Error> (+7 overloads)
export try
Wraps a function execution (sync or async) or a Promise in a
Result
or
ResultAsync
type,
capturing errors and returning them in a structured way.
You can use either a custom catch handler or rely on the safe: true option
to assume the function cannot throw.
@function@typeParamT  - The function type to execute (sync or async) or a Promise type.@typeParamE  - The error type to return if catch is used.@example
Sync  try-catch
import { Result } from '@praha/byethrow';

const fn = Result.try({
try: (x: number) => {
if (x < 0) throw new Error('Negative!');
return x * 2;
},
catch: (error) => new Error('Oops!', { cause: error }),
});

const result = fn(5); // Result.Result<number, Error>
@example
Sync  try-catch with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
immediate: true,
try: () => {
const x = Math.random() * 10 - 5;
if (x < 0) throw new Error('Negative!');
return x * 2;
},
catch: (error) => new Error('Oops!', { cause: error }),
});

// result is Result<number, Error>
@example
Sync  safe
import { Result } from '@praha/byethrow';

const fn = Result.try({
safe: true,
try: (x: number) => x + 1,
});

const result = fn(1); // Result.Result<number, never>
@example
Sync  safe with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
safe: true,
immediate: true,
try: () => Math.random() + 1,
});

// result is Result<number, never>
@example
Async  try-catch
import { Result } from '@praha/byethrow';

const fn = Result.try({
try: async (id: string) => await fetch(`/api/data/${id}`),
catch: (error) => new Error('Oops!', { cause: error }),
});

const result = await fn('abc'); // Result.ResultAsync<Response, Error>
@example
Async  try-catch with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
immediate: true,
try: () => fetch('/api/data'),
catch: (error) => new Error('Fetch failed', { cause: error }),
});

// result is ResultAsync<Response, Error>
@example
Async  safe
import { Result } from '@praha/byethrow';

const fn = Result.try({
safe: true,
try: async () => await Promise.resolve('ok'),
});

const result = await fn(); // Result.ResultAsync<string, never>
@example
Async  safe with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
safe: true,
immediate: true,
try: () => Promise.resolve('ok'),
});

// result is ResultAsync<string, never>
@categoryCreatorstry({
  
try: (id: string) => {
    id: string;
    name: string;
}
try: (
id: stringid: string) => {
    return { 
id: stringid, 
name: stringname: 'John Doe' };
  },
  
catch: (error: unknown) => Errorcatch: (
error: unknownerror) => new 
var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)
Error('Failed to find user', { 
ErrorOptions.cause?: unknowncause: 
error: unknownerror }),
});

const 
const result: Result.Result<{
    id: string;
    name: string;
}, Error>
result = 
import ResultResult.
const pipe: <Result.Result<string, never>, Result.Result<string, Error>, Result.Result<{
    id: string;
    name: string;
}, Error>>(a: Result.Result<string, never>, ab: (a: Result.Result<string, never>) => Result.Result<string, Error>, bc: (b: Result.Result<string, Error>) => Result.Result<{
    id: string;
    name: string;
}, Error>) => Result.Result<{
    id: string;
    name: string;
}, Error> (+25 overloads)
pipe(
  
import ResultResult.
const succeed: <string>(value: string) => Result.Result<string, never> (+1 overload)succeed('u123'),
  
import ResultResult.
const andThrough: <Result.Result<string, never>, Result.Failure<Error> | Result.Success<void>>(fn: (a: string) => Result.Failure<Error> | Result.Success<void>) => (result: Result.Result<string, never>) => Result.Result<string, Error> (+1 overload)andThrough(
const validateId: (id: string) => Result.Failure<Error> | Result.Success<void>validateId),
  
import ResultResult.
const andThen: <Result.Result<string, Error>, Result.Result<{
    id: string;
    name: string;
}, Error>>(fn: (a: string) => Result.Result<{
    id: string;
    name: string;
}, Error>) => (result: Result.Result<string, Error>) => Result.Result<{
    id: string;
    name: string;
}, Error> (+1 overload)
andThen(
const findUser: (id: string) => Result.Result<{
    id: string;
    name: string;
}, Error>
findUser),
);

if (
import ResultResult.
const isSuccess: <{
    id: string;
    name: string;
}>(result: Result.Result<{
    id: string;
    name: string;
}, unknown>) => result is Result.Success<{
    id: string;
    name: string;
}>
Type guard to check if a
Result
is a
Success
.
@function@typeParamT  - The type of the success value.@paramresult  - The Result to check.@returnstrue if the result is a Success, otherwise false.@example
import { Result } from '@praha/byethrow';

const result: Result.Result<number, string> = { type: 'Success', value: 10 };
if (Result.isSuccess(result)) {
  console.log(result.value); // Safe access to value
}
@categoryType  GuardsisSuccess(
const result: Result.Result<{
    id: string;
    name: string;
}, Error>
result)) {
  
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
@seesourceconsole.
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 .1.100log(
const result: Result.Success<{
    id: string;
    name: string;
}>
result.
value: {
    id: string;
    name: string;
}
value); // User found: John Doe
}

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

const 
const validateId: (id: string) => R.Failure<Error> | R.Success<void>validateId = (
id: stringid: string) => {
  if (!
id: stringid.
String.startsWith(searchString: string, position?: number): boolean
Returns true if the sequence of elements of searchString converted to a String is the
same as the corresponding elements of this object (converted to a String) starting at
position. Otherwise returns false.startsWith('u')) {
    return 
import RR.
const fail: <Error>(error: Error) => R.Result<never, Error> (+1 overload)fail(new 
var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)
Error('Invalid ID format'));
  }
  return 
import RR.
const succeed: () => R.ResultFor<never, void, never> (+1 overload)succeed();
};

const 
const findUser: (id: string) => R.Result<{
    id: string;
    name: string;
}, Error>
findUser = 
import RR.
try<(id: string) => {
    id: string;
    name: string;
}, Error>(options: {
    try: (id: string) => {
        id: string;
        name: string;
    };
    catch: (error: unknown) => Error;
}): (id: string) => R.Result<{
    id: string;
    name: string;
}, Error> (+7 overloads)
export try
Wraps a function execution (sync or async) or a Promise in a
Result
or
ResultAsync
type,
capturing errors and returning them in a structured way.
You can use either a custom catch handler or rely on the safe: true option
to assume the function cannot throw.
@function@typeParamT  - The function type to execute (sync or async) or a Promise type.@typeParamE  - The error type to return if catch is used.@example
Sync  try-catch
import { Result } from '@praha/byethrow';

const fn = Result.try({
try: (x: number) => {
if (x < 0) throw new Error('Negative!');
return x * 2;
},
catch: (error) => new Error('Oops!', { cause: error }),
});

const result = fn(5); // Result.Result<number, Error>
@example
Sync  try-catch with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
immediate: true,
try: () => {
const x = Math.random() * 10 - 5;
if (x < 0) throw new Error('Negative!');
return x * 2;
},
catch: (error) => new Error('Oops!', { cause: error }),
});

// result is Result<number, Error>
@example
Sync  safe
import { Result } from '@praha/byethrow';

const fn = Result.try({
safe: true,
try: (x: number) => x + 1,
});

const result = fn(1); // Result.Result<number, never>
@example
Sync  safe with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
safe: true,
immediate: true,
try: () => Math.random() + 1,
});

// result is Result<number, never>
@example
Async  try-catch
import { Result } from '@praha/byethrow';

const fn = Result.try({
try: async (id: string) => await fetch(`/api/data/${id}`),
catch: (error) => new Error('Oops!', { cause: error }),
});

const result = await fn('abc'); // Result.ResultAsync<Response, Error>
@example
Async  try-catch with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
immediate: true,
try: () => fetch('/api/data'),
catch: (error) => new Error('Fetch failed', { cause: error }),
});

// result is ResultAsync<Response, Error>
@example
Async  safe
import { Result } from '@praha/byethrow';

const fn = Result.try({
safe: true,
try: async () => await Promise.resolve('ok'),
});

const result = await fn(); // Result.ResultAsync<string, never>
@example
Async  safe with immediate execution
import { Result } from '@praha/byethrow';

const result = Result.try({
safe: true,
immediate: true,
try: () => Promise.resolve('ok'),
});

// result is ResultAsync<string, never>
@categoryCreatorstry({
  
try: (id: string) => {
    id: string;
    name: string;
}
try: (
id: stringid: string) => {
    return { 
id: stringid, 
name: stringname: 'John Doe' };
  },
  
catch: (error: unknown) => Errorcatch: (
error: unknownerror) => new 
var Error: ErrorConstructor
new (message?: string, options?: ErrorOptions) => Error (+1 overload)
Error('Failed to find user', { 
ErrorOptions.cause?: unknowncause: 
error: unknownerror }),
});

const 
const result: R.Result<{
    id: string;
    name: string;
}, Error>
result = 
import RR.
const pipe: <R.Result<string, never>, R.Result<string, Error>, R.Result<{
    id: string;
    name: string;
}, Error>>(a: R.Result<string, never>, ab: (a: R.Result<string, never>) => R.Result<string, Error>, bc: (b: R.Result<string, Error>) => R.Result<{
    id: string;
    name: string;
}, Error>) => R.Result<{
    id: string;
    name: string;
}, Error> (+25 overloads)
pipe(
  
import RR.
const succeed: <string>(value: string) => R.Result<string, never> (+1 overload)succeed('u123'),
  
import RR.
const andThrough: <R.Result<string, never>, R.Failure<Error> | R.Success<void>>(fn: (a: string) => R.Failure<Error> | R.Success<void>) => (result: R.Result<string, never>) => R.Result<string, Error> (+1 overload)andThrough(
const validateId: (id: string) => R.Failure<Error> | R.Success<void>validateId),
  
import RR.
const andThen: <R.Result<string, Error>, R.Result<{
    id: string;
    name: string;
}, Error>>(fn: (a: string) => R.Result<{
    id: string;
    name: string;
}, Error>) => (result: R.Result<string, Error>) => R.Result<{
    id: string;
    name: string;
}, Error> (+1 overload)
andThen(
const findUser: (id: string) => R.Result<{
    id: string;
    name: string;
}, Error>
findUser),
);

if (
import RR.
const isSuccess: <{
    id: string;
    name: string;
}>(result: R.Result<{
    id: string;
    name: string;
}, unknown>) => result is R.Success<{
    id: string;
    name: string;
}>
Type guard to check if a
Result
is a
Success
.
@function@typeParamT  - The type of the success value.@paramresult  - The Result to check.@returnstrue if the result is a Success, otherwise false.@example
import { Result } from '@praha/byethrow';

const result: Result.Result<number, string> = { type: 'Success', value: 10 };
if (Result.isSuccess(result)) {
  console.log(result.value); // Safe access to value
}
@categoryType  GuardsisSuccess(
const result: R.Result<{
    id: string;
    name: string;
}, Error>
result)) {
  
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
@seesourceconsole.
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 .1.100log(
const result: R.Success<{
    id: string;
    name: string;
}>
result.
value: {
    id: string;
    name: string;
}
value); // User found: John Doe
}