Chain class

A chain of stack traces.

A stack chain is a collection of one or more stack traces that collectively represent the path from main through nested function calls to a particular code location, usually where an error was thrown. Multiple stack traces are necessary when using asynchronous functions, since the program's stack is reset before each asynchronous callback is run.

Stack chains can be automatically tracked using Chain.capture. This sets up a new Zone in which the current stack chain is tracked and can be accessed using new Chain.current. Any errors that would be top-leveled in the zone can be handled, along with their associated chains, with the onError callback. For example:

Chain.capture(() {
  // ...
}, onError: (error, stackChain) {
  print("Caught error $error\n"


Chain(Iterable<Trace> traces)
Returns a new Chain comprised of traces.
Chain.current([int level = 0])
Returns the current stack chain. [...]
Chain.forTrace(StackTrace trace)
Returns the stack chain associated with trace. [...]
Chain.parse(String chain)
Parses a string representation of a stack chain. [...]


terse Chain
Returns a terser version of this. [...]
traces → List<Trace>
The stack traces that make up this chain. [...]
hashCode → int
The hash code for this object.
read-only, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited


foldFrames(bool predicate(Frame frame), {bool terse: false}) Chain
Returns a new Chain based on this where multiple stack frames matching predicate are folded together. [...]
toString() → String
Returns a string representation of this object.
toTrace() Trace
Converts this to a Trace. [...]
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.


operator ==(dynamic other) → bool
The equality operator.

Static Methods

capture<T>(T callback(), {void onError(dynamic error, Chain chain), bool when: true, bool errorZone: true}) → T
If when is true, runs callback in a Zone in which the current stack chain is tracked and automatically associated with (most) errors. [...]
disable<T>(T callback(), {bool when: true}) → T
If when is true and this is called within a Chain.capture zone, runs callback in a Zone in which chain capturing is disabled. [...]
track(dynamic futureOrStream) → dynamic
Returns futureOrStream unmodified. [...]
@Deprecated("Chain.track is not necessary in Dart 1.7+.")