You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
37 lines
1.2 KiB
Lua
37 lines
1.2 KiB
Lua
local Observable = require "rx.observable"
|
|
local util = require "rx.util"
|
|
|
|
--- Returns an Observable that only produces values from the original if they are different from
|
|
-- the previous value.
|
|
-- @arg {function} comparator - A function used to compare 2 values. If unspecified, == is used.
|
|
-- @returns {Observable}
|
|
function Observable:distinctUntilChanged(comparator)
|
|
comparator = comparator or util.eq
|
|
|
|
return Observable.create(function(observer)
|
|
local first = true
|
|
local currentValue = nil
|
|
|
|
local function onNext(value, ...)
|
|
local values = util.pack(...)
|
|
util.tryWithObserver(observer, function()
|
|
if first or not comparator(value, currentValue) then
|
|
observer:onNext(value, util.unpack(values))
|
|
currentValue = value
|
|
first = false
|
|
end
|
|
end)
|
|
end
|
|
|
|
local function onError(message)
|
|
return observer:onError(message)
|
|
end
|
|
|
|
local function onCompleted()
|
|
return observer:onCompleted()
|
|
end
|
|
|
|
return self:subscribe(onNext, onError, onCompleted)
|
|
end)
|
|
end
|