What was requested, and what is available instead
OptionalcauseReadonlynameDiscriminating name for instanceof-free checks.
OptionalstackStaticstackThe Error.stackTraceLimit property specifies the number of stack frames
collected by a stack trace (whether generated by new Error().stack or
Error.captureStackTrace(obj)).
The default value is 10 but may be set to any valid JavaScript number. Changes
will affect any stack trace captured after the value has been changed.
If set to a non-number value, or set to a negative number, stack traces will not capture any frames.
StaticabsentBuilds the error for a binding that is absent entirely.
The requested binding name
Every binding name the Worker's env does carry
The error, ready to throw
StaticcaptureCreates a .stack property on targetObject, which when accessed returns
a string representing the location in the code at which
Error.captureStackTrace() was called.
const myObject = {};
Error.captureStackTrace(myObject);
myObject.stack; // Similar to `new Error().stack`
The first line of the trace will be prefixed with
${myObject.name}: ${myObject.message}.
The optional constructorOpt argument accepts a function. If given, all frames
above constructorOpt, including constructorOpt, will be omitted from the
generated stack trace.
The constructorOpt argument is useful for hiding implementation
details of error generation from the user. For instance:
function a() {
b();
}
function b() {
c();
}
function c() {
// Create an error without stack trace to avoid calculating the stack trace twice.
const { stackTraceLimit } = Error;
Error.stackTraceLimit = 0;
const error = new Error();
Error.stackTraceLimit = stackTraceLimit;
// Capture the stack trace above function b
Error.captureStackTrace(error, b); // Neither function c, nor b is included in the stack trace
throw error;
}
a();
OptionalconstructorOpt: FunctionStaticprepareStaticwrongBuilds the error for a binding that is present with the wrong shape.
The requested binding name
The shape that was expected, for the message
The error, ready to throw
A binding the configuration names is absent from the Worker's
env, or is present with the wrong shape.A missing binding is a deployment error — a stanza absent from
wrangler.toml, a name typo, a preview environment that was never given the namespace. Throwing with the requested name and the names that are present turns a downstreamundefined is not a functioninto a message that says what to fix.Since
0.2.0