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35 lines
952 B
Lua
35 lines
952 B
Lua
local Observable = require "rx.observable"
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local util = require "rx.util"
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--- Returns a new Observable that produces a default set of items if the source Observable produces
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-- no values.
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-- @arg {*...} values - Zero or more values to produce if the source completes without emitting
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-- anything.
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-- @returns {Observable}
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function Observable:defaultIfEmpty(...)
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local defaults = util.pack(...)
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return Observable.create(function(observer)
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local hasValue = false
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local function onNext(...)
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hasValue = true
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observer:onNext(...)
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end
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local function onError(e)
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observer:onError(e)
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end
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local function onCompleted()
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if not hasValue then
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observer:onNext(util.unpack(defaults))
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end
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observer:onCompleted()
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end
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return self:subscribe(onNext, onError, onCompleted)
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end)
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end
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