Logger<unknown, string>A Logger which outputs logs as a string.
Details
For example, a simple log entry is rendered as
timestamp=2025-01-03T14:22:47.570Z level=INFO fiber=#1 message=hello.
Example (Formatting logs as simple strings)
import { Effect, Logger } from "effect"
// Use the simple format logger
const simpleLoggerProgram = Effect.log("Hello Simple Format").pipe(
Effect.provide(Logger.layer([Logger.formatSimple]))
)
// Combine with console output
const consoleSimpleLogger = Logger.withConsoleLog(Logger.formatSimple)
const program = Effect.gen(function*() {
yield* Effect.log("Application started")
yield* Effect.logInfo("Processing data")
yield* Effect.logWarning("Memory usage high")
}).pipe(
Effect.provide(Logger.layer([consoleSimpleLogger]))
)constructors
Source effect/Logger.ts:5441 lines
export const const formatSimple: Logger<
unknown,
string
>
const formatSimple: {
log: (options: Options<unknown>) => string;
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; <…;
}
A Logger which outputs logs as a string.
Details
For example, a simple log entry is rendered as
timestamp=2025-01-03T14:22:47.570Z level=INFO fiber=#1 message=hello.
Example (Formatting logs as simple strings)
import { Effect, Logger } from "effect"
// Use the simple format logger
const simpleLoggerProgram = Effect.log("Hello Simple Format").pipe(
Effect.provide(Logger.layer([Logger.formatSimple]))
)
// Combine with console output
const consoleSimpleLogger = Logger.withConsoleLog(Logger.formatSimple)
const program = Effect.gen(function*() {
yield* Effect.log("Application started")
yield* Effect.logInfo("Processing data")
yield* Effect.logWarning("Memory usage high")
}).pipe(
Effect.provide(Logger.layer([consoleSimpleLogger]))
)
formatSimple = import effecteffect.const loggerMake: <Message, Output>(
log: (
options: Logger.Options<Message>
) => Output
) => Logger.Logger<Message, Output>
const format: (
quoteValue: (s: string) => string,
space?: number | string | undefined
) => ({
cause,
date,
fiber,
logLevel,
message,
}: Options<unknown>) => string
Used by both
formatSimple
and
formatLogFmt
to render a log
message.
format(const escapeDoubleQuotes: (
s: string
) => string
Escapes double quotes in a string.
escapeDoubleQuotes))