Context.Reference<boolean>Context reference for controlling whether trace timing is enabled globally. When set to false, spans will not contain timing information (trace time will always be set to zero).
When to use
Use to disable or re-enable timing capture for spans in the current context.
Example (Toggling trace timing)
import { Effect, References } from "effect"
const tracingControl = Effect.gen(function*() {
// Check if trace timing is enabled (default is true)
const current = yield* References.TracerTimingEnabled
console.log(current) // true
// Disable trace timing globally
yield* Effect.provideService(
Effect.gen(function*() {
// Spans will not having timing information in this context
const isEnabled = yield* References.TracerTimingEnabled
console.log(isEnabled) // false
}),
References.TracerTimingEnabled,
false
)
// Re-enable trace timing
yield* Effect.provideService(
Effect.gen(function*() {
// Spans will have timing information in this context
const isEnabled = yield* References.TracerTimingEnabled
console.log(isEnabled) // true
}),
References.TracerTimingEnabled,
true
)
})export const const TracerTimingEnabled: Context.Reference<boolean>const TracerTimingEnabled: {
defaultValue: () => Shape;
of: (this: void, self: boolean) => boolean;
context: (self: boolean) => Context.Context<never>;
use: (f: (service: boolean) => Effect<A, E, R>) => Effect<A, E, R>;
useSync: (f: (service: boolean) => A) => Effect<A, never, never>;
Identifier: Identifier;
Service: Shape;
key: string;
stack: string | undefined;
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; <…;
toString: () => string;
toJSON: () => unknown;
}
Context reference for controlling whether trace timing is enabled globally. When set
to false, spans will not contain timing information (trace time will always
be set to zero).
When to use
Use to disable or re-enable timing capture for spans in the current context.
Example (Toggling trace timing)
import { Effect, References } from "effect"
const tracingControl = Effect.gen(function*() {
// Check if trace timing is enabled (default is true)
const current = yield* References.TracerTimingEnabled
console.log(current) // true
// Disable trace timing globally
yield* Effect.provideService(
Effect.gen(function*() {
// Spans will not having timing information in this context
const isEnabled = yield* References.TracerTimingEnabled
console.log(isEnabled) // false
}),
References.TracerTimingEnabled,
false
)
// Re-enable trace timing
yield* Effect.provideService(
Effect.gen(function*() {
// Spans will have timing information in this context
const isEnabled = yield* References.TracerTimingEnabled
console.log(isEnabled) // true
}),
References.TracerTimingEnabled,
true
)
})
TracerTimingEnabled: import ContextContext.interface Reference<in out Shape>Service key with a lazily computed default value.
Details
When a Reference is requested from a Context that does not contain an
override, Context getters that resolve references return the cached default
value instead of failing.
Example (Defining a reference with a default value)
import { Context } from "effect"
// Define a reference with a default value
const LoggerRef: Context.Reference<{ log: (msg: string) => void }> =
Context.Reference("Logger", {
defaultValue: () => ({ log: (msg: string) => console.log(msg) })
})
// The reference can be used without explicit provision
const context = Context.empty()
const logger = Context.get(context, LoggerRef) // Uses default value
Creates a context key with a default value.
When to use
Use when you need to define a context key with a lazily computed default
value.
Details
Context.Reference allows you to create a key that can hold a value. You
can provide a default value for the service, which will automatically be used
when the context is accessed, or override it with a custom implementation
when needed. The default value is computed lazily and cached on the
reference.
Example (Creating references with default values)
import { Context } from "effect"
// Create a reference with a default value
const LoggerRef = Context.Reference("Logger", {
defaultValue: () => ({ log: (msg: string) => console.log(msg) })
})
// The reference provides the default value when accessed from an empty context
const context = Context.empty()
const logger = Context.get(context, LoggerRef)
// You can also override the default value
const customContext = Context.make(LoggerRef, {
log: (msg: string) => `Custom: ${msg}`
})
const customLogger = Context.get(customContext, LoggerRef)
Reference<boolean> = import referencesreferences.const TracerTimingEnabled: Context.Reference<boolean>const TracerTimingEnabled: {
defaultValue: () => Shape;
of: (this: void, self: boolean) => boolean;
context: (self: boolean) => Context.Context<never>;
use: (f: (service: boolean) => Effect<A, E, R>) => Effect<A, E, R>;
useSync: (f: (service: boolean) => A) => Effect<A, never, never>;
Identifier: Identifier;
Service: Shape;
key: string;
stack: string | undefined;
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; <…;
toString: () => string;
toJSON: () => unknown;
}