InternalOptions provided to this test
Optional[SIGNAL]Bail out on the first failed test point
OptionalcbNumeric identifier for this test
Method that writes to stderr when debug: true is set in the options,
or no-ops otherwise
number of spaces to indent the TAP stream
Nesting level, for serialization to node test runner
Note that this is zero for parent-less tests, and also zero for the first level of children.
Do not emit the TAP version 14 line at the start
Options provided to this test
Do not elide extraneous whitespace and empty lines.
true if the stream can be read
Set upon test completion when a child test is ready to be processed by its parent.
True if this test should be buffered and only emit data if it fails
Treat non-TAP data as an error.
May be set with pragma +strict in the TAP stream, or unset with
pragma: -strict.
Set to true when the test times out, so its failure status can be determined later.
true if the stream can be written
Static ReadonlycaptureValue: Symbol.for('nodejs.rejection')
See how to write a custom rejection handler.
StaticcaptureValue: boolean
Change the default captureRejections option on all new EventEmitter objects.
StaticdefaultBy default, a maximum of 10 listeners can be registered for any single
event. This limit can be changed for individual EventEmitter instances
using the emitter.setMaxListeners(n) method. To change the default
for allEventEmitter instances, the events.defaultMaxListeners property
can be used. If this value is not a positive number, a RangeError is thrown.
Take caution when setting the events.defaultMaxListeners because the
change affects all EventEmitter instances, including those created before
the change is made. However, calling emitter.setMaxListeners(n) still has
precedence over events.defaultMaxListeners.
This is not a hard limit. The EventEmitter instance will allow
more listeners to be added but will output a trace warning to stderr indicating
that a "possible EventEmitter memory leak" has been detected. For any single
EventEmitter, the emitter.getMaxListeners() and emitter.setMaxListeners() methods can be used to
temporarily avoid this warning:
import { EventEmitter } from 'node:events';
const emitter = new EventEmitter();
emitter.setMaxListeners(emitter.getMaxListeners() + 1);
emitter.once('event', () => {
// do stuff
emitter.setMaxListeners(Math.max(emitter.getMaxListeners() - 1, 0));
});
The --trace-warnings command-line flag can be used to display the
stack trace for such warnings.
The emitted warning can be inspected with process.on('warning') and will
have the additional emitter, type, and count properties, referring to
the event emitter instance, the event's name and the number of attached
listeners, respectively.
Its name property is set to 'MaxListenersExceededWarning'.
Static ReadonlyerrorThis symbol shall be used to install a listener for only monitoring 'error' events. Listeners installed using this symbol are called before the regular 'error' listeners are called.
Installing a listener using this symbol does not change the behavior once an 'error' event is emitted. Therefore, the process will still crash if no
regular 'error' listener is installed.
True if the stream has been aborted.
No-op setter. Stream aborted status is set via the AbortSignal provided in the constructor options.
true if this is an async stream
Set to true to make this stream async.
Once set, it cannot be unset, as this would potentially cause incorrect behavior. Ie, a sync stream can be made async, but an async stream cannot be safely made sync.
The amount of data stored in the buffer waiting to be read.
For Buffer strings, this will be the total byte length.
For string encoding streams, this will be the string character length,
according to JavaScript's string.length logic.
For objectMode streams, this is a count of the items waiting to be
emitted.
true if the stream has been forcibly destroyed
true if the 'end' event has been emitted
The BufferEncoding currently in use, or null
true if the stream is currently in a flowing state, meaning that any writes will be immediately emitted.
True if this is an objectMode stream
true if the stream is currently in a paused state
Boolean indicating whether the underlying stream can be written to, or if it has been ended.
StaticisAlias for isStream
Former export location, maintained for backwards compatibility.
Optional[captureRest...args: AnyRestAlias for Minipass#on
Rest...args: WorkerEvents[Event]Destroy a stream, preventing it from being used for any further purpose.
If the stream has a close() method, then it will be called on
destruction.
After destruction, any attempt to write data, read data, or emit most events will be ignored.
If an error argument is provided, then it will be emitted in an 'error' event.
Optionaler: unknownMark the test as ended. In this base class, this is a no-op, but in @tapjs/core!test-base.TestBase, it also triggers the other end-of-test operations.
Returns an array listing the events for which the emitter has registered
listeners. The values in the array are strings or Symbols.
import { EventEmitter } from 'node:events';
const myEE = new EventEmitter();
myEE.on('foo', () => {});
myEE.on('bar', () => {});
const sym = Symbol('symbol');
myEE.on(sym, () => {});
console.log(myEE.eventNames());
// Prints: [ 'foo', 'bar', Symbol(symbol) ]
Returns the current max listener value for the EventEmitter which is either
set by emitter.setMaxListeners(n) or defaults to defaultMaxListeners.
Returns the number of listeners listening for the event named eventName.
If listener is provided, it will return how many times the listener is found
in the list of the listeners of the event.
The name of the event being listened for
Optionallistener: FunctionThe event handler function
Returns a copy of the array of listeners for the event named eventName.
server.on('connection', (stream) => {
console.log('someone connected!');
});
console.log(util.inspect(server.listeners('connection')));
// Prints: [ [Function] ]
Mostly identical to EventEmitter.off
If a 'data' event handler is removed, and it was the last consumer (ie, there are no pipe destinations or other 'data' event listeners), then the flow of data will stop until there is another consumer or Minipass#resume is explicitly called.
Rest...args: WorkerEvents[Event]Mostly identical to EventEmitter.on, with the following
behavior differences to prevent data loss and unnecessary hangs:
Adding a 'data' event handler will trigger the flow of data
Adding a 'readable' event handler when there is data waiting to be read will cause 'readable' to be emitted immediately.
Adding an 'endish' event handler ('end', 'finish', etc.) which has already passed will cause the event to be emitted immediately and all handlers removed.
Adding an 'error' event handler after an error has been emitted will cause the event to be re-emitted immediately with the error previously raised.
Rest...args: WorkerEvents[Event]Method called when the parser encounters a bail out
Extended by @tapjs/core!test-base.TestBase
Optionalreason: stringAdds a one-time listener function for the event named eventName. The
next time eventName is triggered, this listener is removed and then invoked.
server.once('connection', (stream) => {
console.log('Ah, we have our first user!');
});
Returns a reference to the EventEmitter, so that calls can be chained.
By default, event listeners are invoked in the order they are added. The emitter.prependOnceListener() method can be used as an alternative to add the
event listener to the beginning of the listeners array.
import { EventEmitter } from 'node:events';
const myEE = new EventEmitter();
myEE.once('foo', () => console.log('a'));
myEE.prependOnceListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
// b
// a
The name of the event.
The callback function
Rest...args: any[]Adds the listener function to the beginning of the listeners array for the
event named eventName. No checks are made to see if the listener has
already been added. Multiple calls passing the same combination of eventName
and listener will result in the listener being added, and called, multiple times.
server.prependListener('connection', (stream) => {
console.log('someone connected!');
});
Returns a reference to the EventEmitter, so that calls can be chained.
The name of the event.
The callback function
Rest...args: any[]Adds a one-timelistener function for the event named eventName to the beginning of the listeners array. The next time eventName is triggered, this
listener is removed, and then invoked.
server.prependOnceListener('connection', (stream) => {
console.log('Ah, we have our first user!');
});
Returns a reference to the EventEmitter, so that calls can be chained.
The name of the event.
The callback function
Rest...args: any[]Returns a copy of the array of listeners for the event named eventName,
including any wrappers (such as those created by .once()).
import { EventEmitter } from 'node:events';
const emitter = new EventEmitter();
emitter.once('log', () => console.log('log once'));
// Returns a new Array with a function `onceWrapper` which has a property
// `listener` which contains the original listener bound above
const listeners = emitter.rawListeners('log');
const logFnWrapper = listeners[0];
// Logs "log once" to the console and does not unbind the `once` event
logFnWrapper.listener();
// Logs "log once" to the console and removes the listener
logFnWrapper();
emitter.on('log', () => console.log('log persistently'));
// Will return a new Array with a single function bound by `.on()` above
const newListeners = emitter.rawListeners('log');
// Logs "log persistently" twice
newListeners[0]();
emitter.emit('log');
Low-level explicit read method.
In objectMode, the argument is ignored, and one item is returned if available.
n is the number of bytes (or in the case of encoding streams,
characters) to consume. If n is not provided, then the entire buffer
is returned, or null is returned if no data is available.
If n is greater that the amount of data in the internal buffer,
then null is returned.
Optionaln: null | numberMostly identical to EventEmitter.removeAllListeners
If all 'data' event handlers are removed, and they were the last consumer (ie, there are no pipe destinations), then the flow of data will stop until there is another consumer or Minipass#resume is explicitly called.
Optionalev: EventAlias for Minipass#off
Rest...args: WorkerEvents[Event]Resume the stream if it is currently in a paused state
If called when there are no pipe destinations or data event listeners,
this will place the stream in a "discarded" state, where all data will
be thrown away. The discarded state is removed if a pipe destination or
data handler is added, if pause() is called, or if any synchronous or
asynchronous iteration is started.
By default EventEmitters will print a warning if more than 10 listeners are
added for a particular event. This is a useful default that helps finding
memory leaks. The emitter.setMaxListeners() method allows the limit to be
modified for this specific EventEmitter instance. The value can be set to Infinity (or 0) to indicate an unlimited number of listeners.
Returns a reference to the EventEmitter, so that calls can be chained.
Fully unhook a piped destination stream.
If the destination stream was the only consumer of this stream (ie,
there are no other piped destinations or 'data' event listeners)
then the flow of data will stop until there is another consumer or
Minipass#resume is explicitly called.
StaticaddExperimentalListens once to the abort event on the provided signal.
Listening to the abort event on abort signals is unsafe and may
lead to resource leaks since another third party with the signal can
call e.stopImmediatePropagation(). Unfortunately Node.js cannot change
this since it would violate the web standard. Additionally, the original
API makes it easy to forget to remove listeners.
This API allows safely using AbortSignals in Node.js APIs by solving these
two issues by listening to the event such that stopImmediatePropagation does
not prevent the listener from running.
Returns a disposable so that it may be unsubscribed from more easily.
import { addAbortListener } from 'node:events';
function example(signal) {
let disposable;
try {
signal.addEventListener('abort', (e) => e.stopImmediatePropagation());
disposable = addAbortListener(signal, (e) => {
// Do something when signal is aborted.
});
} finally {
disposable?.[Symbol.dispose]();
}
}
Disposable that removes the abort listener.
StaticgetReturns a copy of the array of listeners for the event named eventName.
For EventEmitters this behaves exactly the same as calling .listeners on
the emitter.
For EventTargets this is the only way to get the event listeners for the
event target. This is useful for debugging and diagnostic purposes.
import { getEventListeners, EventEmitter } from 'node:events';
{
const ee = new EventEmitter();
const listener = () => console.log('Events are fun');
ee.on('foo', listener);
console.log(getEventListeners(ee, 'foo')); // [ [Function: listener] ]
}
{
const et = new EventTarget();
const listener = () => console.log('Events are fun');
et.addEventListener('foo', listener);
console.log(getEventListeners(et, 'foo')); // [ [Function: listener] ]
}
StaticgetReturns the currently set max amount of listeners.
For EventEmitters this behaves exactly the same as calling .getMaxListeners on
the emitter.
For EventTargets this is the only way to get the max event listeners for the
event target. If the number of event handlers on a single EventTarget exceeds
the max set, the EventTarget will print a warning.
import { getMaxListeners, setMaxListeners, EventEmitter } from 'node:events';
{
const ee = new EventEmitter();
console.log(getMaxListeners(ee)); // 10
setMaxListeners(11, ee);
console.log(getMaxListeners(ee)); // 11
}
{
const et = new EventTarget();
console.log(getMaxListeners(et)); // 10
setMaxListeners(11, et);
console.log(getMaxListeners(et)); // 11
}
StaticlistenerA class method that returns the number of listeners for the given eventName registered on the given emitter.
import { EventEmitter, listenerCount } from 'node:events';
const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// Prints: 2
The emitter to query
The event name
Staticonimport { on, EventEmitter } from 'node:events';
import process from 'node:process';
const ee = new EventEmitter();
// Emit later on
process.nextTick(() => {
ee.emit('foo', 'bar');
ee.emit('foo', 42);
});
for await (const event of on(ee, 'foo')) {
// The execution of this inner block is synchronous and it
// processes one event at a time (even with await). Do not use
// if concurrent execution is required.
console.log(event); // prints ['bar'] [42]
}
// Unreachable here
Returns an AsyncIterator that iterates eventName events. It will throw
if the EventEmitter emits 'error'. It removes all listeners when
exiting the loop. The value returned by each iteration is an array
composed of the emitted event arguments.
An AbortSignal can be used to cancel waiting on events:
import { on, EventEmitter } from 'node:events';
import process from 'node:process';
const ac = new AbortController();
(async () => {
const ee = new EventEmitter();
// Emit later on
process.nextTick(() => {
ee.emit('foo', 'bar');
ee.emit('foo', 42);
});
for await (const event of on(ee, 'foo', { signal: ac.signal })) {
// The execution of this inner block is synchronous and it
// processes one event at a time (even with await). Do not use
// if concurrent execution is required.
console.log(event); // prints ['bar'] [42]
}
// Unreachable here
})();
process.nextTick(() => ac.abort());
Use the close option to specify an array of event names that will end the iteration:
import { on, EventEmitter } from 'node:events';
import process from 'node:process';
const ee = new EventEmitter();
// Emit later on
process.nextTick(() => {
ee.emit('foo', 'bar');
ee.emit('foo', 42);
ee.emit('close');
});
for await (const event of on(ee, 'foo', { close: ['close'] })) {
console.log(event); // prints ['bar'] [42]
}
// the loop will exit after 'close' is emitted
console.log('done'); // prints 'done'
Optionaloptions: StaticEventEmitterIteratorOptionsAn AsyncIterator that iterates eventName events emitted by the emitter
Optionaloptions: StaticEventEmitterIteratorOptionsStaticonceCreates a Promise that is fulfilled when the EventEmitter emits the given
event or that is rejected if the EventEmitter emits 'error' while waiting.
The Promise will resolve with an array of all the arguments emitted to the
given event.
This method is intentionally generic and works with the web platform EventTarget interface, which has no special'error' event
semantics and does not listen to the 'error' event.
import { once, EventEmitter } from 'node:events';
import process from 'node:process';
const ee = new EventEmitter();
process.nextTick(() => {
ee.emit('myevent', 42);
});
const [value] = await once(ee, 'myevent');
console.log(value);
const err = new Error('kaboom');
process.nextTick(() => {
ee.emit('error', err);
});
try {
await once(ee, 'myevent');
} catch (err) {
console.error('error happened', err);
}
The special handling of the 'error' event is only used when events.once() is used to wait for another event. If events.once() is used to wait for the
'error' event itself, then it is treated as any other kind of event without
special handling:
import { EventEmitter, once } from 'node:events';
const ee = new EventEmitter();
once(ee, 'error')
.then(([err]) => console.log('ok', err.message))
.catch((err) => console.error('error', err.message));
ee.emit('error', new Error('boom'));
// Prints: ok boom
An AbortSignal can be used to cancel waiting for the event:
import { EventEmitter, once } from 'node:events';
const ee = new EventEmitter();
const ac = new AbortController();
async function foo(emitter, event, signal) {
try {
await once(emitter, event, { signal });
console.log('event emitted!');
} catch (error) {
if (error.name === 'AbortError') {
console.error('Waiting for the event was canceled!');
} else {
console.error('There was an error', error.message);
}
}
}
foo(ee, 'foo', ac.signal);
ac.abort(); // Abort waiting for the event
ee.emit('foo'); // Prints: Waiting for the event was canceled!
Optionaloptions: StaticEventEmitterOptionsOptionaloptions: StaticEventEmitterOptionsStaticprocStaticsetimport { setMaxListeners, EventEmitter } from 'node:events';
const target = new EventTarget();
const emitter = new EventEmitter();
setMaxListeners(5, target, emitter);
Optionaln: numberA non-negative number. The maximum number of listeners per EventTarget event.
Rest...eventTargets: (EventEmitter<DefaultEventMap> | EventTarget)[]InternalbufferedTrue if this test should be buffered and only processed on completion
OptionaldeferredA Deferred promise wrapper that is resolved when this test completes.
TapWrap AsyncResource that limits the async-hook-domain
the async-hook-domain that catches throws and Promise rejections
Internaloutputthe TAP stream data for buffered tests
OptionalparentParent test of this TAP stream
The tap parser attached to this TAP stream
high resolution bigint time when this test started
OptionaltimerThe timer that fires when the test times out
InternalEventEmitter emit method, but closes the
@tapjs/core!base.Base#hook and
@tapjs/core!base.Base#hookDomain when emitting 'end'.
Rest...data: WorkerEvents[Event]InternalMethod called when the parser completes and emits its final results
Extended by @tapjs/core!worker.Worker and @tapjs/core!tap.TAP classes
InternalRun the main test function. Called by
@tapjs/core!test-base.TestBase when starting a subtest.
Initializes the TapWrap hook
InternalCalled when a timeout occurs. Only exposed because it has to be called and/or extended by other classes, which all have their own sorts of timeout behavior specific to the type of thing they represent.
Optionalexpired?: stringInternalStream write method.
For buffered tests, this collects the output in the
@tapjs/core!base.Base#output
field. Sets @tapjs/core!base.Base#printedOutput to true when
called.
Note: you probably never need to call this. Instead, use the various assertion methods and other parts of the API.
Set the amount of time in milliseconds before this test is considered
a timeout. The time is counted from right now, so for example, repeatedly
calling t.setTimeout(100) can keep it going indefinitely, as long as
you call it more often than every 100ms.
Calling setTimeout(0) will remove the timer and allow the test to run
indefinitely.
True if this test emitted a bailout
The count of all assertions that this stream emitted
Unrecoverable TAP protocol errors in the stream
High resolution time in ns that this test took to complete.
Lists of todo, skip, and failure test points. If passes: true is
set in the options, then passing test points will also be tracked.
the name of this test
OptionalresultsSet on completion. The results of the test run.
Amount of time in milliseconds that this test took to complete.
True if the test has printed some output of any kind
Returns true if this test has begun
Class representing a TAP generating node worker thread
Instantiated by
t.worker(), typically.