<E>(cause: Cause<E>): stringFormats a Cause as a human-readable string for logging or debugging.
When to use
Use to render a whole cause as one human-readable string for logs or diagnostics.
Details
Delegates to prettyErrors to convert each reason to an Error,
then joins their stack traces with newlines. Nested Error.cause chains
are rendered inline with indentation:
ErrorName: message
at ...
at ... {
[cause]: NestedError: message
at ...
}Span annotations are appended to the relevant stack frames when available.
Gotchas
Rendering an empty cause produces an empty string because there are no errors to render.
Example (Rendering a cause)
import { Cause } from "effect"
const rendered = Cause.pretty(Cause.fail("something went wrong"))
console.log(rendered.includes("something went wrong")) // trueexport const const pretty: <E>(
cause: Cause<E>
) => string
Formats a Cause as a human-readable string for logging or debugging.
When to use
Use to render a whole cause as one human-readable string for logs or
diagnostics.
Details
Delegates to
prettyErrors
to convert each reason to an Error,
then joins their stack traces with newlines. Nested Error.cause chains
are rendered inline with indentation:
ErrorName: message
at ...
at ... {
[cause]: NestedError: message
at ...
}
Span annotations are appended to the relevant stack frames when available.
Gotchas
Rendering an empty cause produces an empty string because there are no
errors to render.
Example (Rendering a cause)
import { Cause } from "effect"
const rendered = Cause.pretty(Cause.fail("something went wrong"))
console.log(rendered.includes("something went wrong")) // true
pretty: <function (type parameter) E in <E>(cause: Cause<E>): stringE>(cause: Cause<E>(parameter) cause: {
reasons: ReadonlyArray<Reason<E>>;
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;
}
interface Cause<out E>A structured representation of how an Effect failed.
When to use
Use to preserve the full structured failure information for an effect instead
of collapsing it to a single error value.
Details
Access the individual failure entries through the reasons array, then
narrow each entry with
isFailReason
,
isDieReason
, or
- Use
hasFails
/
hasDies
/
hasInterrupts
to test
for the presence of specific reason kinds without iterating.
- Use
findError
/
findDefect
to extract the first value
of a given kind.
- Use
combine
to merge two causes.
Cause implements Equal — two causes with the same reasons (by value)
compare as equal.
Example (Creating and inspecting a cause)
import { Cause } from "effect"
const cause = Cause.fail("Something went wrong")
console.log(cause.reasons.length) // 1
console.log(Cause.isFailReason(cause.reasons[0])) // true
Companion namespace for the Cause interface.
Cause<function (type parameter) E in <E>(cause: Cause<E>): stringE>) => string = import effecteffect.const causePretty: <E>(
cause: Cause.Cause<E>
) => string