ReplaySubject;

doc/README.md

@@ -97,6 +97,10 @@ RxLua
  - [subscribe](#subscribeonnext-onerror-oncompleted)
  - [onNext](#onnextvalues)
  - [getValue](#getvalue)
+- [ReplaySubject](#replaysubject)
+ - [create](#createbuffersize)
+ - [subscribe](#subscribeonnext-onerror-oncompleted)
+ - [onNext](#onnextvalues)
 
 # Subscription
 
@@ -928,3 +932,39 @@ Pushes zero or more values to the BehaviorSubject. They will be broadcasted to a
 
 Returns the last value emitted by the Subject, or the initial value passed to the constructor if nothing has been emitted yet.
 
+# ReplaySubject
+
+A Subject that provides new Subscribers with some or all of the most recently produced values upon subscription.
+
+---
+
+#### `.create(bufferSize)`
+
+Creates a new ReplaySubject.
+
+| Name | Type | Default | Description |
+|------|------|---------|-------------|
+| `bufferSize` | number (optional) | | The number of values to send to new subscribers. If nil, an infinite buffer is used (note that this could lead to memory issues). |
+
+---
+
+#### `:subscribe(onNext, onError, onCompleted)`
+
+Creates a new Observer and attaches it to the ReplaySubject. Immediately broadcasts the most contents of the buffer to the Observer.
+
+| Name | Type | Default | Description |
+|------|------|---------|-------------|
+| `onNext` | function | | Called when the ReplaySubject produces a value. |
+| `onError` | function | | Called when the ReplaySubject terminates due to an error. |
+| `onCompleted` | function | | Called when the ReplaySubject completes normally. |
+
+---
+
+#### `:onNext(values)`
+
+Pushes zero or more values to the ReplaySubject. They will be broadcasted to all Observers.
+
+| Name | Type | Default | Description |
+|------|------|---------|-------------|
+| `values` | *... | | |
+

rx.lua

@@ -1952,6 +1952,64 @@ end
 
 BehaviorSubject.__call = BehaviorSubject.onNext
 
+--- @class ReplaySubject
+-- @description A Subject that provides new Subscribers with some or all of the most recently
+-- produced values upon subscription.
+local ReplaySubject = setmetatable({}, Subject)
+ReplaySubject.__index = ReplaySubject
+ReplaySubject.__tostring = util.constant('ReplaySubject')
+
+--- Creates a new ReplaySubject.
+-- @arg {number=} bufferSize - The number of values to send to new subscribers. If nil, an infinite
+-- buffer is used (note that this could lead to memory issues).
+-- @returns {ReplaySubject}
+function ReplaySubject.create(n)
+ local self = {
+ observers = {},
+ stopped = false,
+ buffer = {},
+ bufferSize = n
+ }
+
+ return setmetatable(self, ReplaySubject)
+end
+
+--- Creates a new Observer and attaches it to the ReplaySubject. Immediately broadcasts the most
+-- contents of the buffer to the Observer.
+-- @arg {function} onNext - Called when the ReplaySubject produces a value.
+-- @arg {function} onError - Called when the ReplaySubject terminates due to an error.
+-- @arg {function} onCompleted - Called when the ReplaySubject completes normally.
+function ReplaySubject:subscribe(onNext, onError, onCompleted)
+ local observer
+
+ if util.isa(onNext, Observer) then
+ observer = onNext
+ else
+ observer = Observer.create(onNext, onError, onCompleted)
+ end
+
+ local subscription = Subject.subscribe(self, observer)
+
+ for i = 1, #self.buffer do
+ observer:onNext(util.unpack(self.buffer[i]))
+ end
+
+ return subscription
+end
+
+--- Pushes zero or more values to the ReplaySubject. They will be broadcasted to all Observers.
+-- @arg {*...} values
+function ReplaySubject:onNext(...)
+ table.insert(self.buffer, util.pack(...))
+ if self.bufferSize and #self.buffer > self.bufferSize then
+ table.remove(self.buffer, 1)
+ end
+
+ return Subject.onNext(self, ...)
+end
+
+ReplaySubject.__call = ReplaySubject.onNext
+
 Observable.wrap = Observable.buffer
 Observable['repeat'] = Observable.replicate
 
@@ -1964,5 +2022,6 @@ return {
  CooperativeScheduler = CooperativeScheduler,
  Subject = Subject,
  AsyncSubject = AsyncSubject,
- BehaviorSubject = BehaviorSubject
+ BehaviorSubject = BehaviorSubject,
+ ReplaySubject = ReplaySubject
 }

src/subjects/replaysubject.lua

@@ -0,0 +1,63 @@
+local Subject = require 'subjects/subject'
+local Observer = require 'observer'
+local util = require 'util'
+
+--- @class ReplaySubject
+-- @description A Subject that provides new Subscribers with some or all of the most recently
+-- produced values upon subscription.
+local ReplaySubject = setmetatable({}, Subject)
+ReplaySubject.__index = ReplaySubject
+ReplaySubject.__tostring = util.constant('ReplaySubject')
+
+--- Creates a new ReplaySubject.
+-- @arg {number=} bufferSize - The number of values to send to new subscribers. If nil, an infinite
+-- buffer is used (note that this could lead to memory issues).
+-- @returns {ReplaySubject}
+function ReplaySubject.create(n)
+ local self = {
+ observers = {},
+ stopped = false,
+ buffer = {},
+ bufferSize = n
+ }
+
+ return setmetatable(self, ReplaySubject)
+end
+
+--- Creates a new Observer and attaches it to the ReplaySubject. Immediately broadcasts the most
+-- contents of the buffer to the Observer.
+-- @arg {function} onNext - Called when the ReplaySubject produces a value.
+-- @arg {function} onError - Called when the ReplaySubject terminates due to an error.
+-- @arg {function} onCompleted - Called when the ReplaySubject completes normally.
+function ReplaySubject:subscribe(onNext, onError, onCompleted)
+ local observer
+
+ if util.isa(onNext, Observer) then
+ observer = onNext
+ else
+ observer = Observer.create(onNext, onError, onCompleted)
+ end
+
+ local subscription = Subject.subscribe(self, observer)
+
+ for i = 1, #self.buffer do
+ observer:onNext(util.unpack(self.buffer[i]))
+ end
+
+ return subscription
+end
+
+--- Pushes zero or more values to the ReplaySubject. They will be broadcasted to all Observers.
+-- @arg {*...} values
+function ReplaySubject:onNext(...)
+ table.insert(self.buffer, util.pack(...))
+ if self.bufferSize and #self.buffer > self.bufferSize then
+ table.remove(self.buffer, 1)
+ end
+
+ return Subject.onNext(self, ...)
+end
+
+ReplaySubject.__call = ReplaySubject.onNext
+
+return ReplaySubject

tests/replaysubject.lua

@@ -0,0 +1,87 @@
+describe('ReplaySubject', function()
+ describe('create', function()
+ it('returns a ReplaySubject', function()
+ expect(Rx.ReplaySubject.create()).to.be.an(Rx.ReplaySubject)
+ end)
+
+ it('sets an appropriate buffer size if it is specified', function()
+ local subject = Rx.ReplaySubject.create(2)
+ local observer = Rx.Observer.create()
+ local onNext = spy(observer, '_onNext')
+ subject:onNext(1)
+ subject:onNext(2)
+ subject:onNext(3)
+ subject:subscribe(observer)
+ expect(onNext).to.equal({{2}, {3}})
+ end)
+
+ it('keeps an infinite buffer if no buffer size is specified', function()
+ local subject = Rx.ReplaySubject.create()
+ local observer = Rx.Observer.create()
+ local onNext = spy(observer, '_onNext')
+ subject:onNext(1)
+ subject:onNext(2)
+ subject:onNext(3)
+ subject:subscribe(observer)
+ expect(onNext).to.equal({{1}, {2}, {3}})
+ end)
+ end)
+
+ describe('subscribe', function()
+ it('returns a Subscription', function()
+ local subject = Rx.ReplaySubject.create()
+ local observer = Rx.Observer.create()
+ expect(subject:subscribe(observer)).to.be.an(Rx.Subscription)
+ end)
+
+ it('accepts 3 functions as arguments', function()
+ local onNext, onCompleted = spy(), spy()
+ local subject = Rx.ReplaySubject.create()
+ subject:subscribe(onNext, nil, onCompleted)
+ subject:onNext(5)
+ subject:onCompleted()
+ expect(onNext).to.equal({{5}})
+ expect(#onCompleted).to.equal(1)
+ end)
+
+ it('calls onNext with the current buffer', function()
+ local subject = Rx.ReplaySubject.create(2)
+ local observer = Rx.Observer.create()
+ local onNext = spy(observer, '_onNext')
+ subject:onNext(1)
+ subject:onNext(2)
+ subject:onNext(3)
+ subject:subscribe(observer)
+ expect(onNext).to.equal({{2}, {3}})
+ end)
+ end)
+
+ describe('onNext', function()
+ it('pushes values to all subscribers', function()
+ local observers = {}
+ local spies = {}
+ for i = 1, 2 do
+ observers[i] = Rx.Observer.create()
+ spies[i] = spy(observers[i], '_onNext')
+ end
+
+ local subject = Rx.ReplaySubject.create()
+ subject:subscribe(observers[1])
+ subject:subscribe(observers[2])
+ subject:onNext(1)
+ subject:onNext(2)
+ subject:onNext(3)
+ expect(spies[1]).to.equal({{1}, {2}, {3}})
+ expect(spies[2]).to.equal({{1}, {2}, {3}})
+ end)
+
+ it('can be called using function syntax', function()
+ local observer = Rx.Observer.create()
+ local subject = Rx.ReplaySubject.create()
+ local onNext = spy(observer, 'onNext')
+ subject:subscribe(observer)
+ subject(4)
+ expect(#onNext).to.equal(1)
+ end)
+ end)
+end)

tests/runner.lua

@@ -60,7 +60,8 @@ else
  'subscription',
  'subject',
  'asyncsubject',
- 'behaviorsubject'
+ 'behaviorsubject',
+ 'replaysubject'
  }
 
  for i, file in ipairs(files) do

tools/concat.lua

@@ -61,6 +61,7 @@ local files = {
  'src/subjects/subject.lua',
  'src/subjects/asyncsubject.lua',
  'src/subjects/behaviorsubject.lua',
+ 'src/subjects/replaysubject.lua',
  'src/aliases.lua'
 }
 
@@ -80,7 +81,8 @@ local footer = [[return {
  CooperativeScheduler = CooperativeScheduler,
  Subject = Subject,
  AsyncSubject = AsyncSubject,
- BehaviorSubject = BehaviorSubject
+ BehaviorSubject = BehaviorSubject,
+ ReplaySubject = ReplaySubject
 }]]
 
 local output = ''