Package: effect
Module: Logger
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]))
)
Signature
declare const formatSimple: Logger<unknown, string>
Since v4.0.0