@most/core

empty

 empty(): Stream

Create a Stream containing no events and ends immediately.

see

https://mostcore.readthedocs.io/en/latest/api.html#empty

Parameter	Type	Default	Description

Returns Stream

never

 never(): Stream

Create a Stream containing no events and never ends.

see

https://mostcore.readthedocs.io/en/latest/api.html#never

Parameter	Type	Default	Description

Returns Stream

now

 now(x: *): Stream

Create a Stream containing a single event at time 0.

see

https://mostcore.readthedocs.io/en/latest/api.html#now

Parameter	Type	Default	Description
x	*		event data

Returns Stream

Example

// Log the array [1, 2] to the console right away
a = now([1, 2]).tap(log)

at

 at(t: Number, x: *): Stream

Create a Stream containing a single event at a specific time.

see

https://mostcore.readthedocs.io/en/latest/api.html#at

Parameter	Type	Default	Description
t	Number		time
x	*		event data

Returns Stream

Example

// Log the array [1, 2] to the console after 1 second
a = at(1000, [1, 2]).tap(log)

periodic

 periodic(period: Number): Stream

Create an infinite Stream containing events that occur at a specified
Period. The first event occurs at time 0, and the event values are
undefined.

see

https://mostcore.readthedocs.io/en/latest/api.html#periodic

Parameter	Type	Default	Description
period	Number		period (ms)

Returns Stream

Example

// Generate a periodic signal with 500 ms interval and randomize the stream values.
a = periodic(500).map(() => Math.random()).tap(log);

throwError

 throwError(error: Error): Stream

Create a Stream that fails with the provided Error at time 0. This can be
useful for functions that need to return a Stream and also need to propagate
an error.

see

https://mostcore.readthedocs.io/en/latest/api.html#throwerror

Parameter	Type	Default	Description
error	Error		Error

Returns Stream

startWith

 startWith(x: *, source: Stream): Stream

Prepend an event at time 0.

see

https://mostcore.readthedocs.io/en/latest/api.html#startwith

Parameter	Type	Default	Description
x	*		Event data
source	Stream		Source Stream

Returns Stream The source stream starting with the start element

continueWith

 continueWith(f: Function, source: Stream): Stream

Replace the end of a Stream with another Stream. When stream ends, f
will be called and must return a Stream.

see

https://mostcore.readthedocs.io/en/latest/api.html?highlight=continuewith#cont}inuewit

Parameter	Type	Default	Description
f	Function		Function that returns a stream
source	Stream		Source Stream

Returns Stream

map

 map(f: Function, source: Stream): Stream

Apply a function to each event value.

see

https://mostcore.readthedocs.io/en/latest/api.html#map

Parameter	Type	Default	Description
f	Function		Unary function
source	Stream		Source stream

Returns Stream

Example

// Apply a function (in this example, double) to all events in a stream
f = x => 2 * x;
a = periodic(500).constant(1).accum()
  .map(f)
  .tap(log)

constant

 constant(x: *, source: Stream): Stream

Replace each event value with x.

see

https://mostcore.readthedocs.io/en/latest/api.html#constant

Parameter	Type	Default	Description
x	*		event data
source	Stream		Source stream

Returns Stream

tap

 tap(f: Function, source: Stream): Stream

Perform a side effect for each event in a Stream. For each event in stream,
f is called, but the value of its result is ignored. If f fails (i.e.,
throws an error), then the returned Stream will also fail. The Stream
returned by tap will contain the same events as the original Stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#tap

Parameter	Type	Default	Description
f	Function		Tap function
source	Stream		Source stream

Returns Stream

Example

// Apply a function with side effects, to log the values to the console
a = periodic(500).rand().tap(log);

ap

 ap(fs: Stream<Function>, source: Stream): Stream

Apply the latest function in a Stream of functions to the latest value of
another Stream. In effect, ap applies a time-varying function to a
time-varying value.

see

https://mostcore.readthedocs.io/en/latest/api.html#ap

Parameter	Type	Default	Description
fs	Stream<Function>		Function stream
source	Stream		Source stream

Returns Stream

scan

 scan(f: Function, initial: *, source: Stream): Stream

Incrementally accumulate results, starting with the provided initial value.

see

https://mostcore.readthedocs.io/en/latest/api.html#scan

Parameter	Type	Default	Description
f	Function		Scanning reducer
initial	*		Initial Value
source	Stream		Source stream

Returns Stream

Example

// Accumulate the values of a constant stream
a = periodic(500).constant(2)
  .scan((s, x) => s + x, 0)
  .tap(log);

loop

 loop(stepper: Function, seed: *, source: Stream): Stream

Accumulate results using a feedback loop that emits one value and feeds back
another to be used in the next iteration.It allows you to maintain and update a “state” (a.k.a. feedback, a.k.a. seed
for the next iteration) while emitting a different value. In contrast, scan
feeds back and produces the same value.

see

https://mostcore.readthedocs.io/en/latest/api.html#loop

Parameter	Type	Default	Description
stepper	Function		Stepper function
seed	*		Seed
source	Stream		Source stream

Returns Stream

withItems

 withItems(items: Array, source: Stream): Stream

Replace each event value with the array item at the respective index. The
resulting Stream will contain the same number of events as the input Stream,
or array.length events, whichever is less.

see

https://mostcore.readthedocs.io/en/latest/api.html#withitems

Parameter	Type	Default	Description
items	Array		Items array
source	Stream		Source stream

Returns Stream

zipItems

 zipItems(f: Function, items: Array, source: Stream): Stream

Apply a function to the latest event and the array value at the respective
index. The resulting Stream will contain the same number of events as the
input Stream, or array.length events, whichever is less.

see

https://mostcore.readthedocs.io/en/latest/api.html#zipitems

Parameter	Type	Default	Description
f	Function		Combinator function
items	Array		Items
source	Stream		Source stream

Returns Stream

switchLatest

 switchLatest(source: Stream): Stream

Given a higher-order Stream, return a new Stream that adopts the behavior of
(i.e., emits the events of) the most recent inner Stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#switchlatest

Parameter	Type	Default	Description
source	Stream		higher-order stream

Returns Stream

join

 join(source: Stream): Stream

Given a higher-order Stream, return a new Stream that merges all the inner
Streams as they arrive.

see

https://mostcore.readthedocs.io/en/latest/api.html#join

Parameter	Type	Default	Description
source	Stream		higher-order Stream

Returns Stream

chain

 chain(f: Function, source: Stream): Stream

Transform each event in stream into a new Stream, and then merge each into
the resulting Stream. Note that f must return a Stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#chain

Parameter	Type	Default	Description
f	Function		function returning a stream
source	Stream		Source stream

Returns Stream

concatMap

 concatMap(f: Function, source: Stream): Stream

Transform each event in stream into a Stream, and then concatenate each
onto the end of the resulting Stream. Note that f must return a Stream.The mapping function f is applied lazily. That is, f is called only once
it is time to concatenate a new stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#concatmap

Parameter	Type	Default	Description
f	Function		Function returning a stream
source	Stream		Source stream

Returns Stream

mergeConcurrently

 mergeConcurrently(concurrency: Number, source: Stream): Stream

Given a higher-order Stream, return a new Stream that merges inner Streams
as they arrive up to the specified concurrency. Once concurrency number of
Streams are being merged, newly arriving Streams will be merged after an
existing one ends.

see

https://mostcore.readthedocs.io/en/latest/api.html#mergeconcurrently

Parameter	Type	Default	Description
concurrency	Number		concurrency level
source	Stream		Higher-order stream

Returns Stream

mergeMapConcurrently

 mergeMapConcurrently(f: Function, concurrency: Number, source: Stream): Stream

Lazily apply a function f to each event in a Stream, merging them into the
resulting Stream at the specified concurrency. Once concurrency number of
Streams are being merged, newly arriving Streams will be merged after an
existing one ends.

see

https://mostcore.readthedocs.io/en/latest/api.html#mergemapconcurrently

Parameter	Type	Default	Description
f	Function		Unary function
concurrency	Number		concurrency level
source	Stream		event stream

Returns Stream

merge

 merge(stream1: Stream, source: Stream): Stream

Create a new Stream containing events from two Streams.Merging creates a new Stream containing all events from the two original
Streams without affecting the time of the events. You can think of the
events from the input Streams simply being interleaved into the new, merged
Stream. A merged Stream ends when all of its input Streams have ended.

see

https://mostcore.readthedocs.io/en/latest/api.html#merge

Parameter	Type	Default	Description
stream1	Stream		Event stream 1
source	Stream		Event stream 2

Returns Stream

Example

a = periodic(500).take(3).constant('a');
b = periodic(100).take(3).constant(2);
c = a.merge(b).tap(log);

combine

 combine(f: Function, stream1: Stream, source: Stream): Stream

Apply a function to the most recent event from each Stream when a new event
arrives on any Stream.Note that combine waits for at least one event to arrive on all input
Streams before it produces any events.

see

https://mostcore.readthedocs.io/en/latest/api.html#combine

Parameter	Type	Default	Description
f	Function		Combinator function
stream1	Stream		Event stream 1
source	Stream		Event stream 2

Returns Stream

zip

 zip(f: Function, stream1: Stream, source: Stream): Stream

Apply a function to corresponding pairs of events from the inputs Streams.

see

https://mostcore.readthedocs.io/en/latest/api.html#zip

Parameter	Type	Default	Description
f	Function		Combinator function
stream1	Stream		Event stream 1
source	Stream		Event stream 2

Returns Stream

sample

 sample(source: Stream, sampler: Stream): Stream

For each event in a sampler Stream, replace the event value with the latest
value in another Stream. The resulting Stream will contain the same number
of events as the sampler Stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#sample

Parameter	Type	Default	Description
source	Stream		value stream
sampler	Stream		Sampler stream

Returns Stream

Example

// Sample a noise signal from a stream of click events
noise = periodic(20).rand().plot({ legend: 'noise' });
click = click(doc).sample(noise).tap(log);

resample

 resample(sampler: Stream, source: Stream): Stream

Like sample, but the value stream and sampler streams are switched

see

https://mostcore.readthedocs.io/en/latest/api.html#sample

Parameter	Type	Default	Description
sampler	Stream		Sampler stream
source	Stream		value stream

Returns Stream

Example

// Sample a noise signal from a stream of click events
noise = periodic(20).rand().plot({ legend: 'noise' });
click = noise.resample(click(doc)).tap(log);

snapshot

 snapshot(f: Function, values: Stream, source: Stream): Stream

For each event in a sampler Stream, apply a function to combine its value
with the most recent event value in another Stream. The resulting Stream
will contain the same number of events as the sampler Stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#snapshot

Parameter	Type	Default	Description
f	Function		Snapshot function
values	Stream		Value stream
source	Stream		Source stream

Returns Stream

filter

 filter(p: Function, source: Stream): Stream

Retain only events for which a predicate is truthy.

see

https://mostcore.readthedocs.io/en/latest/api.html#filter

Parameter	Type	Default	Description
p	Function		Predicate
source	Stream		Source event stream

Returns Stream

Example

a = periodic(200).rand().filter(x => x > 0.8).tap(log);

skipRepeats

 skipRepeats(source: Stream): Stream

Remove adjacent repeated events.

see

https://mostcore.readthedocs.io/en/latest/api.html#skiprepeats

Parameter	Type	Default	Description
source	Stream		Source event stream

Returns Stream

skipRepeatsWith

 skipRepeatsWith(equals: Function, source: Stream): Stream

Remove adjacent repeated events, using the provided equality function to
compare adjacent events.

see

https://mostcore.readthedocs.io/en/latest/api.html#skiprepeatswith

Parameter	Type	Default	Description
equals	Function		Equality function
source	Stream		Source event stream

Returns Stream

slice

 slice(start: Number, end: Number, source: Stream): Stream

Keep only events in a range, where start <= index < end, and index is the
ordinal index of an event in stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#id48

Parameter	Type	Default	Description
start	Number		start index
end	Number		end index
source	Stream		Source event stream

Returns Stream

take

 take(n: Number, source: Stream): Stream

Keep at most the first n events from stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#take

Parameter	Type	Default	Description
n	Number		Number of events
source	Stream		Source event stream

Returns Stream

skip

 skip(n: Number, source: Stream): Stream

Discard the first n events from stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#skip

Parameter	Type	Default	Description
n	Number		Number of events
source	Stream		Source event stream

Returns Stream

takeWhile

 takeWhile(p: Function, source: Stream): Stream

Keep all events until predicate returns false, and discard the rest.

see

https://mostcore.readthedocs.io/en/latest/api.html#takewhile

Parameter	Type	Default	Description
p	Function		Predicate
source	Stream		Source event stream

Returns Stream

skipWhile

 skipWhile(p: Function, source: Stream): Stream

Discard all events until predicate returns false, and keep the rest.

see

https://mostcore.readthedocs.io/en/latest/api.html#skipwhile

Parameter	Type	Default	Description
p	Function		Predicate
source	Stream		Source event stream

Returns Stream

skipAfter

 skipAfter(p: Function, source: Stream): Stream

Discard all events after the first event for which predicate returns true.

see

https://mostcore.readthedocs.io/en/latest/api.html#skipafter

Parameter	Type	Default	Description
p	Function		Predicate
source	Stream		Source event stream

Returns Stream

until

 until(endSignal: Stream, source: Stream): Stream

Keep all events in one Stream until the first event occurs in another.

see

https://mostcore.readthedocs.io/en/latest/api.html#until

Parameter	Type	Default	Description
endSignal	Stream		End signal
source	Stream		Source stream

Returns Stream

since

 since(startSignal: Stream, source: Stream): Stream

Discard all events in one Stream until the first event occurs in another.

see

https://mostcore.readthedocs.io/en/latest/api.html#since

Parameter	Type	Default	Description
startSignal	Stream		Start signal
source	Stream		Source stream

Returns Stream

during

 during(timeWindow: Stream, source: Stream): Stream

Keep events that occur during a time window defined by a higher-order Stream.

Parameter	Type	Default	Description
timeWindow	Stream		Higher order stream defining a time window
source	Stream		Source stream

Returns Stream

delay

 delay(delayTime: Number, source: Stream): Stream

Timeshift a Stream by the specified Delay.

see

https://mostcore.readthedocs.io/en/latest/api.html#id57

Parameter	Type	Default	Description
delayTime	Number		Delay time (ms)
source	Stream		Source stream

Returns Stream

withLocalTime

 withLocalTime(origin: Number, source: Stream): Stream

Create a Stream with localized Time values, whose origin (i.e., time 0) is
at the specified Time on the Scheduler provided when the Stream is observed
with runEffects or run.When implementing custom higher-order Stream combinators, such as chain, you
should use withLocalTime to localize “inner” Streams before running them.

see

https://mostcore.readthedocs.io/en/latest/api.html#withlocaltime

Parameter	Type	Default	Description
origin	Number		origin time value
source	Stream		Source stream

Returns Stream

throttle

 throttle(period: Number, source: Stream): Stream

Limit the rate of events by suppressing events that occur too often

see

https://mostcore.readthedocs.io/en/latest/api.html#throttle

Parameter	Type	Default	Description
period	Number		Throttle period
source	Stream		Source stream

Returns Stream

debounce

 debounce(period: Number, source: Stream): Stream

Wait for a burst of events to subside and keep only the last event in the
burst.If the Stream ends while there is a pending debounced event (e.g., via
until), the pending event will occur just before the Stream ends.

see

https://mostcore.readthedocs.io/en/latest/api.html#debounce

Parameter	Type	Default	Description
period	Number		Debounce period
source	Stream		Source stream

Returns Stream

fromPromise

 fromPromise(promise: Promise): Stream

Create a Stream containing a promise’s value.

see

https://mostcore.readthedocs.io/en/latest/api.html#frompromise

Parameter	Type	Default	Description
promise	Promise		WHAT ?????? {"type":"linkReference","identifier":"description","referenceType":"shortcut","children":[{"type":"text","value":"description","position":{"start":{"line":1,"column":2,"offset":1},"end":{"line":1,"column":13,"offset":12},"indent":[]}}],"position":{"start":{"line":1,"column":1,"offset":0},"end":{"line":1,"column":14,"offset":13},"indent":[]}}

Returns Stream

awaitPromises

 awaitPromises(source: Stream): Stream

Turn a Stream of promises into a Stream containing the promises’ values.

see

https://mostcore.readthedocs.io/en/latest/api.html#awaitpromises

Parameter	Type	Default	Description
source	Stream		Stream of promises

Returns Stream

recoverWith

 recoverWith(f: Function, source: Stream): Stream

Recover from a stream failure by calling a function to create a new Stream.

see

https://mostcore.readthedocs.io/en/latest/api.html#recoverwith

Parameter	Type	Default	Description
f	Function		Function returning a new stream from an error
source	Stream		Source stream

Returns Stream

multicast

 multicast(source: Stream): Stream

Returns a Stream equivalent to the original but which can be shared more
efficiently among multiple consumers.

see

https://mostcore.readthedocs.io/en/latest/api.html#multicast

Parameter	Type	Default	Description
source	Stream		Source stream

Returns Stream

click

 click(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM Click events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

dblclick

 dblclick(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM dblclick events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

mousedown

 mousedown(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM mousedown events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

mouseup

 mouseup(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM mouseup events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

mousemove

 mousemove(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM mousemove events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

mouseover

 mouseover(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM mouseover events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

mouseenter

 mouseenter(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM mouseenter events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

mouseout

 mouseout(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM mouseout events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

mouseleave

 mouseleave(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM mouseleave events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

touchcancel

 touchcancel(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM touchcancel events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

touchend

 touchend(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM touchend events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

touchmove

 touchmove(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM touchmove events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream

touchstart

 touchstart(node: HTMLElement, capture: Boolean): Stream

Create a stream of DOM touchstart events

see

https://github.com/mostjs/dom-event

Parameter	Type	Default	Description
node	HTMLElement		DOM Node
capture	Boolean	false	use capture

Returns Stream