<Output, Output2>(f: (output: Output) => Output2): <Message>(
self: Logger<Message, Output>
) => Logger<Message, Output2>
<Message, Output, Output2>(
self: Logger<Message, Output>,
f: (output: Output) => Output2
): Logger<Message, Output2>Transforms the output of a Logger using the provided function.
When to use
Use when an existing logger's output should be transformed without recreating the logging logic.
Example (Transforming logger output)
import { Logger } from "effect"
// Create a logger that outputs objects
const structuredLogger = Logger.make((options) => ({
level: options.logLevel,
message: options.message,
timestamp: options.date.toISOString()
}))
// Transform the output to JSON strings
const jsonStringLogger = Logger.map(
structuredLogger,
(output) => JSON.stringify(output)
)
// Transform to uppercase messages
const uppercaseLogger = Logger.map(
structuredLogger,
(output) => ({ ...output, message: String(output.message).toUpperCase() })
)mapping
Source effect/Logger.ts:22711 lines
export const const map: (<Output, Output2>(
f: (output: Output) => Output2
) => <Message>(
self: Logger<Message, Output>
) => Logger<Message, Output2>) &
(<Message, Output, Output2>(
self: Logger<Message, Output>,
f: (output: Output) => Output2
) => Logger<Message, Output2>)
Transforms the output of a Logger using the provided function.
When to use
Use when an existing logger's output should be transformed without recreating the
logging logic.
Example (Transforming logger output)
import { Logger } from "effect"
// Create a logger that outputs objects
const structuredLogger = Logger.make((options) => ({
level: options.logLevel,
message: options.message,
timestamp: options.date.toISOString()
}))
// Transform the output to JSON strings
const jsonStringLogger = Logger.map(
structuredLogger,
(output) => JSON.stringify(output)
)
// Transform to uppercase messages
const uppercaseLogger = Logger.map(
structuredLogger,
(output) => ({ ...output, message: String(output.message).toUpperCase() })
)
map = import dualdual<
<function (type parameter) Output in <Output, Output2>(f: (output: Output) => Output2): <Message>(self: Logger<Message, Output>) => Logger<Message, Output2>Output, function (type parameter) Output2 in <Output, Output2>(f: (output: Output) => Output2): <Message>(self: Logger<Message, Output>) => Logger<Message, Output2>Output2>(
f: (output: Output) => Output2f: (output: Outputoutput: function (type parameter) Output in <Output, Output2>(f: (output: Output) => Output2): <Message>(self: Logger<Message, Output>) => Logger<Message, Output2>Output) => function (type parameter) Output2 in <Output, Output2>(f: (output: Output) => Output2): <Message>(self: Logger<Message, Output>) => Logger<Message, Output2>Output2
) => <function (type parameter) Message in <Message>(self: Logger<Message, Output>): Logger<Message, Output2>Message>(
self: Logger<Message, Output>(parameter) self: {
log: (options: Options<Message>) => Output;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
interface Logger<in Message, out Output>A logger that transforms a runtime log event into an output value.
Details
The runtime calls log with the message, level, cause, fiber, and timestamp
for each log event. Use Logger.layer to install one or more loggers for an
effect.
Example (Creating custom loggers)
import { Effect, Logger } from "effect"
// Create a custom logger that accepts unknown messages and returns void
const stringLogger = Logger.make<unknown, void>((options) => {
console.log(`[${options.logLevel}] ${options.message}`)
})
// Create a logger that accepts any message type and returns a formatted string
const formattedLogger = Logger.make<unknown, string>((options) =>
`${options.date.toISOString()} [${options.logLevel}] ${options.message}`
)
// Use the logger in an Effect program
const program = Effect.log("Hello World").pipe(
Effect.provide(Logger.layer([stringLogger]))
)
Logger<function (type parameter) Message in <Message>(self: Logger<Message, Output>): Logger<Message, Output2>Message, function (type parameter) Output in <Output, Output2>(f: (output: Output) => Output2): <Message>(self: Logger<Message, Output>) => Logger<Message, Output2>Output>
) => interface Logger<in Message, out Output>A logger that transforms a runtime log event into an output value.
Details
The runtime calls log with the message, level, cause, fiber, and timestamp
for each log event. Use Logger.layer to install one or more loggers for an
effect.
Example (Creating custom loggers)
import { Effect, Logger } from "effect"
// Create a custom logger that accepts unknown messages and returns void
const stringLogger = Logger.make<unknown, void>((options) => {
console.log(`[${options.logLevel}] ${options.message}`)
})
// Create a logger that accepts any message type and returns a formatted string
const formattedLogger = Logger.make<unknown, string>((options) =>
`${options.date.toISOString()} [${options.logLevel}] ${options.message}`
)
// Use the logger in an Effect program
const program = Effect.log("Hello World").pipe(
Effect.provide(Logger.layer([stringLogger]))
)
Logger<function (type parameter) Message in <Message>(self: Logger<Message, Output>): Logger<Message, Output2>Message, function (type parameter) Output2 in <Output, Output2>(f: (output: Output) => Output2): <Message>(self: Logger<Message, Output>) => Logger<Message, Output2>Output2>,
<function (type parameter) Message in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Message, function (type parameter) Output in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Output, function (type parameter) Output2 in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Output2>(
self: Logger<Message, Output>(parameter) self: {
log: (options: Options<Message>) => Output;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
interface Logger<in Message, out Output>A logger that transforms a runtime log event into an output value.
Details
The runtime calls log with the message, level, cause, fiber, and timestamp
for each log event. Use Logger.layer to install one or more loggers for an
effect.
Example (Creating custom loggers)
import { Effect, Logger } from "effect"
// Create a custom logger that accepts unknown messages and returns void
const stringLogger = Logger.make<unknown, void>((options) => {
console.log(`[${options.logLevel}] ${options.message}`)
})
// Create a logger that accepts any message type and returns a formatted string
const formattedLogger = Logger.make<unknown, string>((options) =>
`${options.date.toISOString()} [${options.logLevel}] ${options.message}`
)
// Use the logger in an Effect program
const program = Effect.log("Hello World").pipe(
Effect.provide(Logger.layer([stringLogger]))
)
Logger<function (type parameter) Message in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Message, function (type parameter) Output in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Output>,
f: (output: Output) => Output2f: (output: Outputoutput: function (type parameter) Output in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Output) => function (type parameter) Output2 in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Output2
) => interface Logger<in Message, out Output>A logger that transforms a runtime log event into an output value.
Details
The runtime calls log with the message, level, cause, fiber, and timestamp
for each log event. Use Logger.layer to install one or more loggers for an
effect.
Example (Creating custom loggers)
import { Effect, Logger } from "effect"
// Create a custom logger that accepts unknown messages and returns void
const stringLogger = Logger.make<unknown, void>((options) => {
console.log(`[${options.logLevel}] ${options.message}`)
})
// Create a logger that accepts any message type and returns a formatted string
const formattedLogger = Logger.make<unknown, string>((options) =>
`${options.date.toISOString()} [${options.logLevel}] ${options.message}`
)
// Use the logger in an Effect program
const program = Effect.log("Hello World").pipe(
Effect.provide(Logger.layer([stringLogger]))
)
Logger<function (type parameter) Message in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Message, function (type parameter) Output2 in <Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2): Logger<Message, Output2>Output2>
>(2, (self: Logger<Message, Output>(parameter) self: {
log: (options: Options<Message>) => Output;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
f: anyf) => import effecteffect.const loggerMake: <Message, Output>(
log: (
options: Logger.Options<Message>
) => Output
) => Logger.Logger<Message, Output>
options: Options<Message>(parameter) options: {
message: Message;
logLevel: LogLevel.LogLevel;
cause: Cause.Cause<unknown>;
fiber: Fiber.Fiber<unknown, unknown>;
date: Date;
}
f: anyf(self: Logger<Message, Output>(parameter) self: {
log: (options: Options<Message>) => Output;
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
}
options: Options<Message>(parameter) options: {
message: Message;
logLevel: LogLevel.LogLevel;
cause: Cause.Cause<unknown>;
fiber: Fiber.Fiber<unknown, unknown>;
date: Date;
}
Referenced by 1 symbols