streams implementation
This commit is contained in:
Leo Horie
parent
94a8be4fca
commit
b9ce90765d
12 changed files with 1104 additions and 167 deletions
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@ -1,8 +0,0 @@
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"use strict"
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module.exports = function(store) {
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return function() {
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if (arguments.length > 0) store = arguments[0]
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return store
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}
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}
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159
util/stream.js
Normal file
159
util/stream.js
Normal file
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@ -0,0 +1,159 @@
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"use strict"
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var guid = 0, noop = function() {}, HALT = {}
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function createStream() {
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function stream() {
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if (arguments.length > 0) updateStream(stream, arguments[0], undefined)
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return stream._state.value
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}
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initStream(stream, arguments)
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if (arguments.length > 0) updateStream(stream, arguments[0], undefined)
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return stream
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}
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function initStream(stream, args) {
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stream.constructor = createStream
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stream._state = {id: guid++, value: undefined, error: undefined, state: 0, derive: undefined, recover: undefined, deps: {}, parents: [], errorStream: undefined, endStream: undefined}
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stream.map = map, stream.ap = ap, stream.of = createStream
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stream.valueOf = valueOf
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stream.catch = doCatch
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Object.defineProperties(stream, {
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error: {get: function() {
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if (!stream._state.errorStream) {
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var errorStream = function() {
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if (arguments.length > 0) updateStream(stream, undefined, arguments[0])
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return stream._state.error
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}
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initStream(errorStream, [])
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initDependency(errorStream, [stream], noop, noop)
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stream._state.errorStream = errorStream
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}
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return stream._state.errorStream
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}},
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end: {get: function() {
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if (!stream._state.endStream) {
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var endStream = createStream()
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endStream.map(function(value) {
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if (value === true) unregisterStream(stream), unregisterStream(endStream)
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return value
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})
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stream._state.endStream = endStream
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}
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return stream._state.endStream
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}}
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})
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}
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function updateStream(stream, value, error) {
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if (!absorbStream(stream, value, false) && !absorbStream(stream, error, true)) {
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updateState(stream, value, error)
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for (var id in stream._state.deps) updateDependency(stream._state.deps[id], false)
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finalize(stream)
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}
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}
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function updateState(stream, value, error) {
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if (error !== undefined && typeof stream._state.recover === "function") {
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try {updateValues(stream, stream._state.recover(), undefined)}
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catch (e) {updateValues(stream, undefined, e)}
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}
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else updateValues(stream, value, error)
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stream._state.changed = true
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if (stream._state.state !== 2) stream._state.state = 1
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}
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function updateValues(stream, value, error) {
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stream._state.value = value
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stream._state.error = error
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}
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function updateDependency(stream, mustSync) {
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var state = stream._state, parents = state.parents
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if (parents.length > 0 && parents.filter(active).length === parents.length && (mustSync || parents.filter(changed).length > 0)) {
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var failed = parents.filter(errored)
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if (failed.length > 0) updateState(stream, undefined, failed[0]._state.error)
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else {
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try {
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var value = state.derive()
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if (!absorbStream(stream, value)) updateState(stream, value, undefined)
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}
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catch (e) {
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updateState(stream, undefined, e)
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}
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}
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}
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}
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function absorbStream(stream, value, isError) {
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if (value != null && value.constructor === createStream) {
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if (value._state.state === 2) {
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stream.end(true)
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stream(value())
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}
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else if (value._state.error) stream.error(value.error())
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else if (value._state.state === 0) return true
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else if (!isError) stream(value())
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else stream.error(value())
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return true
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}
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return false
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}
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function finalize(stream) {
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stream._state.changed = false
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for (var id in stream._state.deps) stream._state.deps[id]._state.changed = false
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}
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function doCatch(fn) {
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var stream = this
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var derive = function() {return stream._state.value}
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var recover = function() {return fn(stream._state.error)}
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return initDependency(createStream(), [stream], derive, recover)
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}
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function combine(fn, streams) {
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return initDependency(createStream(), streams, function() {
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var failed = streams.filter(errored)
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if (failed.length > 0) throw failed[0]._state.error
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return fn.apply(this, streams.concat([streams.filter(changed)]))
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}, undefined)
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}
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function initDependency(dep, streams, derive, recover) {
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var state = dep._state
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state.derive = derive
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state.recover = recover
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state.parents = streams.filter(notEnded)
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registerDependency(dep, state.parents)
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updateDependency(dep, true)
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return dep
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}
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function registerDependency(stream, parents) {
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for (var i = 0; i < parents.length; i++) {
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parents[i]._state.deps[stream._state.id] = stream
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registerDependency(stream, parents[i]._state.parents)
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}
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}
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function unregisterStream(stream) {
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for (var id in stream._state.deps) {
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var dependent = stream._state.deps[id]
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var index = dependent._state.parents.indexOf(stream)
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if (index > -1) dependent._state.parents.splice(index, 1)
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}
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stream._state.state = 2 //ended
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stream._state.deps = {}
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}
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function map(fn) {return combine(function(stream) {return fn(stream())}, [this])}
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function ap(stream) {return combine(function(s1, s2) {return s1()(s2())}, [this, stream])}
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function valueOf() {return this._state.value}
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function active(stream) {return stream._state.state === 1}
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function changed(stream) {return stream._state.changed}
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function notEnded(stream) {return stream._state.state !== 2}
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function errored(stream) {return stream._state.error}
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function reject(e) {
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var stream = createStream()
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stream.error(e)
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return stream
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}
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module.exports = {stream: createStream, combine: combine, reject: reject}
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@ -6,11 +6,12 @@
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<body>
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<script src="../../module/module.js"></script>
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<script src="../../ospec/ospec.js"></script>
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<script src="../../test-utils/callAsync.js"></script>
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<script src="../../util/prop.js"></script>
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<script src="../../util/withAttr.js"></script>
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<script src="test-prop.js"></script>
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<script src="../../util/stream.js"></script>
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<script src="test-withAttr.js"></script>
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<script src="test-stream.js"></script>
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<script>require("../../ospec/ospec").run()</script>
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</body>
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@ -1,16 +0,0 @@
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"use strict"
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var o = require("../../ospec/ospec")
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var prop = require("../../util/prop")
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o.spec("prop", function() {
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o("works", function() {
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var store = prop(1)
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var initialValue = store()
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store(2)
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var newValue = store()
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o(initialValue).equals(1)
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o(newValue).equals(2)
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})
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})
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779
util/tests/test-stream.js
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779
util/tests/test-stream.js
Normal file
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@ -0,0 +1,779 @@
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"use strict"
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var o = require("../../ospec/ospec")
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var callAsync = require("../../test-utils/callAsync")
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var Stream = require("../../util/stream")
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o.spec("stream", function() {
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o.spec("stream", function() {
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o("works as getter/setter", function() {
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var stream = Stream.stream(1)
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var initialValue = stream()
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stream(2)
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var newValue = stream()
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o(initialValue).equals(1)
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o(newValue).equals(2)
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})
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o("has undefined value by default", function() {
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var stream = Stream.stream()
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o(stream()).equals(undefined)
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})
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o("can update to undefined", function() {
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var stream = Stream.stream(1)
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stream(undefined)
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o(stream()).equals(undefined)
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})
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})
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o.spec("combine", function() {
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o("transforms value", function() {
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var stream = Stream.stream()
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var doubled = Stream.combine(function(s) {return s() * 2}, [stream])
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stream(2)
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o(doubled()).equals(4)
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})
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o("transforms default value", function() {
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var stream = Stream.stream(2)
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var doubled = Stream.combine(function(s) {return s() * 2}, [stream])
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o(doubled()).equals(4)
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})
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o("transforms multiple values", function() {
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var s1 = Stream.stream()
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var s2 = Stream.stream()
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var added = Stream.combine(function(s1, s2) {return s1() + s2()}, [s1, s2])
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s1(2)
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s2(3)
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o(added()).equals(5)
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})
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o("transforms multiple default values", function() {
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var s1 = Stream.stream(2)
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var s2 = Stream.stream(3)
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var added = Stream.combine(function(s1, s2) {return s1() + s2()}, [s1, s2])
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o(added()).equals(5)
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})
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o("transforms mixed default and late-bound values", function() {
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var s1 = Stream.stream(2)
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var s2 = Stream.stream()
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var added = Stream.combine(function(s1, s2) {return s1() + s2()}, [s1, s2])
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s2(3)
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o(added()).equals(5)
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})
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o("combines atomically", function() {
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var count = 0
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var a = Stream.stream()
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var b = Stream.combine(function(a) {return a() * 2}, [a])
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var c = Stream.combine(function(a) {return a() * a()}, [a])
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var d = Stream.combine(function(b, c) {
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count++
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return b() + c()
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}, [b, c])
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a(3)
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o(d()).equals(15)
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o(count).equals(1)
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})
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o("combines default value atomically", function() {
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var count = 0
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var a = Stream.stream(3)
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var b = Stream.combine(function(a) {return a() * 2}, [a])
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var c = Stream.combine(function(a) {return a() * a()}, [a])
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var d = Stream.combine(function(b, c) {
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count++
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return b() + c()
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}, [b, c])
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o(d()).equals(15)
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o(count).equals(1)
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})
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o("combine lists only changed upstreams in last arg", function() {
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var streams = []
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var a = Stream.stream()
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var b = Stream.stream()
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var c = Stream.combine(function(a, b, changed) {
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streams = changed
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}, [a, b])
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a(3)
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b(5)
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o(streams.length).equals(1)
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o(streams[0]).equals(b)
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})
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o("combine lists only changed upstreams in last arg with default value", function() {
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var streams = []
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var a = Stream.stream(3)
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var b = Stream.stream(5)
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var c = Stream.combine(function(a, b, changed) {
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streams = changed
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}, [a, b])
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a(7)
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o(streams.length).equals(1)
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o(streams[0]).equals(a)
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})
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o("combine can return undefined", function() {
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var a = Stream.stream(1)
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var b = Stream.combine(function(a) {
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return undefined
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}, [a])
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o(b()).equals(undefined)
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})
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o("combine absorbs streams", function() {
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var a = Stream.stream(1)
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var b = Stream.combine(function(a) {
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return Stream.stream(2)
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}, [a])
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o(b()).equals(2)
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})
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o("combine absorbs errored streams", function() {
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var a = Stream.stream(1)
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var b = Stream.combine(function(a) {
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return Stream.reject(new Error("error"))
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}, [a])
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o(b()).equals(undefined)
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o(b.error().message).equals("error")
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})
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o("combine absorbs ready streams", function() {
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var count = 0
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var a = Stream.stream(1)
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var b = Stream.combine(function(a) {
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return Stream.stream()
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}, [a])
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var c = Stream.combine(function(b) {
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count++
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return 2
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}, [b])
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o(c()).equals(undefined)
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o(count).equals(0)
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})
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})
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o.spec("end", function() {
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o("end stream works", function() {
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var stream = Stream.stream()
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var doubled = Stream.combine(function(stream) {return stream() * 2}, [stream])
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stream.end(true)
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stream(3)
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o(doubled()).equals(undefined)
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})
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o("end stream works with default value", function() {
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var stream = Stream.stream(2)
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var doubled = Stream.combine(function(stream) {return stream() * 2}, [stream])
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stream.end(true)
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stream(3)
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o(doubled()).equals(4)
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})
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o("cannot add downstream to ended stream", function() {
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var stream = Stream.stream(2)
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stream.end(true)
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var doubled = Stream.combine(function(stream) {return stream() * 2}, [stream])
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stream(3)
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o(doubled()).equals(undefined)
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})
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})
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o.spec("error", function() {
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o("error() works", function() {
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var stream = Stream.stream()
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var errored = Stream.combine(function(stream) {throw new Error("error")}, [stream])
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stream(3)
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o(errored()).equals(undefined)
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o(errored.error().message).equals("error")
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})
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o("error() works with default value", function() {
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var stream = Stream.stream(3)
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var errored = Stream.combine(function(stream) {throw new Error("error")}, [stream])
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o(errored()).equals(undefined)
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o(errored.error().message).equals("error")
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})
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o("error() removes error on valid value", function() {
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var stream = Stream.stream("a")
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var doubled = Stream.combine(function(stream) {
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if (typeof stream() !== "number") throw new Error("error")
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else return stream() * 2
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}, [stream])
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stream(3)
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o(doubled()).equals(6)
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o(doubled.error()).equals(undefined)
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})
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o("error() triggers catch", function() {
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var count = 0
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var stream = Stream.stream(1)
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var handled = stream.catch(function() {
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count++
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return 2
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})
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stream.error(new Error("error"))
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o(handled()).equals(2)
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o(handled.error()).equals(undefined)
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o(count).equals(1)
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})
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o("thrown error propagates downstream", function() {
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var count = 0
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var stream = Stream.stream(1)
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.map(function() {throw new Error("error")})
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.map(function(value) {
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count++
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return value * 2
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})
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.map(function(value) {
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count++
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return value * 3
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})
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o(stream()).equals(undefined)
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o(stream.error().message).equals("error")
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o(count).equals(0)
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})
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o("set error propagates downstream", function() {
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var count = 0
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var stream = Stream.stream()
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var mapped = stream.map(function(value) {
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count++
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return value * 2
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})
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.map(function(value) {
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count++
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return value * 3
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})
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stream.error(new Error("error"))
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o(mapped()).equals(undefined)
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o(mapped.error().message).equals("error")
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o(count).equals(0)
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})
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o("error.map works", function() {
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var stream = Stream.stream(1)
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var mappedFromError = stream.error.map(function(value) {
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return "from" + value.message
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})
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o(mappedFromError()).equals(undefined)
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stream.error(new Error("error"))
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o(mappedFromError()).equals("fromerror")
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})
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o("error from error.map propagates", function() {
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var stream = Stream.stream(1)
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var mappedFromError = stream.error.map(function(value) {
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return "from" + value.message
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}).map(function(value) {
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return "a" + value
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})
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o(mappedFromError()).equals(undefined)
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|
||||
stream.error(new Error("error"))
|
||||
|
||||
o(mappedFromError()).equals("afromerror")
|
||||
})
|
||||
o("error thrown from error.map propagates downstream", function() {
|
||||
var count = 0
|
||||
var stream = Stream.stream(1)
|
||||
var mappedFromError = stream.error.map(function(value) {
|
||||
throw new Error("b")
|
||||
})
|
||||
|
||||
var downstream = mappedFromError.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
o(mappedFromError()).equals(undefined)
|
||||
|
||||
stream.error(new Error("a"))
|
||||
|
||||
o(mappedFromError()).equals(undefined)
|
||||
o(mappedFromError.error().message).equals("b")
|
||||
o(downstream()).equals(undefined)
|
||||
o(downstream.error().message).equals("b")
|
||||
o(count).equals(0)
|
||||
})
|
||||
o("error.map absorbs streams", function() {
|
||||
var stream = Stream.reject(new Error("error"))
|
||||
var error = stream.error.map(function(value) {
|
||||
return Stream.stream(1)
|
||||
})
|
||||
|
||||
o(error()).equals(1)
|
||||
})
|
||||
})
|
||||
o.spec("reject", function() {
|
||||
o("reject works", function() {
|
||||
var stream = Stream.reject(new Error("error"))
|
||||
|
||||
o(stream()).equals(undefined)
|
||||
o(stream.error().message).equals("error")
|
||||
})
|
||||
o("rejected propagates downstream", function() {
|
||||
var count = 0
|
||||
var stream = Stream.reject(new Error("error"))
|
||||
.map(function(value) {
|
||||
count++
|
||||
return value * 2
|
||||
})
|
||||
.map(function(value) {
|
||||
count++
|
||||
return value * 3
|
||||
})
|
||||
|
||||
o(stream()).equals(undefined)
|
||||
o(stream.error().message).equals("error")
|
||||
})
|
||||
o("rejected removes error on value", function() {
|
||||
var stream = Stream.reject(new Error("error"))
|
||||
var doubled = stream.map(function(value) {
|
||||
return value * 2
|
||||
})
|
||||
|
||||
stream(1)
|
||||
|
||||
o(doubled()).equals(2)
|
||||
o(stream.error()).equals(undefined)
|
||||
})
|
||||
o("combined rejected yields first error", function() {
|
||||
var count = 0
|
||||
var a = Stream.reject(new Error("a"))
|
||||
var b = Stream.reject(new Error("b"))
|
||||
var combined = Stream.combine(function(a, b) {
|
||||
count++
|
||||
return a() + b()
|
||||
}, [a, b])
|
||||
|
||||
o(combined()).equals(undefined)
|
||||
o(combined.error().message).equals("a")
|
||||
o(count).equals(0)
|
||||
})
|
||||
})
|
||||
o.spec("catch", function() {
|
||||
o("catch works from reject", function() {
|
||||
var count = 0
|
||||
var stream = Stream.reject(new Error("error")).catch(function(e) {
|
||||
count++
|
||||
return "no" + e.message
|
||||
}).map(function(value) {
|
||||
return value + "mapped"
|
||||
})
|
||||
|
||||
o(count).equals(1)
|
||||
o(stream()).equals("noerrormapped")
|
||||
o(stream.error()).equals(undefined)
|
||||
})
|
||||
o("catch works from combine", function() {
|
||||
var count = 0
|
||||
var stream = Stream.combine(function() {throw new Error("error")}, [Stream.stream(1)]).catch(function(e) {
|
||||
count++
|
||||
return "no" + e.message
|
||||
}).map(function(value) {
|
||||
return value + "mapped"
|
||||
})
|
||||
|
||||
o(count).equals(1)
|
||||
o(stream()).equals("noerrormapped")
|
||||
o(stream.error()).equals(undefined)
|
||||
})
|
||||
o("catch is not called if no error", function() {
|
||||
var count = 0
|
||||
var stream = Stream.stream()
|
||||
var handled = stream.map(function(value) {return value + value}).catch(function(e) {
|
||||
count++
|
||||
return "no" + e.message
|
||||
}).map(function(value) {
|
||||
return value + "mapped"
|
||||
})
|
||||
|
||||
stream("a")
|
||||
|
||||
o(count).equals(0)
|
||||
o(handled()).equals("aamapped")
|
||||
o(handled.error()).equals(undefined)
|
||||
})
|
||||
o("catch is not called if no error with default value", function() {
|
||||
var count = 0
|
||||
var stream = Stream.stream("a").map(function(value) {return value + value}).catch(function(e) {
|
||||
count++
|
||||
return "no" + e.message
|
||||
}).map(function(value) {
|
||||
return value + "mapped"
|
||||
})
|
||||
|
||||
o(count).equals(0)
|
||||
o(stream()).equals("aamapped")
|
||||
o(stream.error()).equals(undefined)
|
||||
})
|
||||
o("throwing from catch rejects", function() {
|
||||
var stream = Stream.reject(new Error("a")).catch(function(e) {
|
||||
throw new Error("b")
|
||||
})
|
||||
var mapped = stream.map(function(value) {return value + "ok"})
|
||||
|
||||
o(stream()).equals(undefined)
|
||||
o(stream.error().message).equals("b")
|
||||
o(mapped()).equals(undefined)
|
||||
o(mapped.error().message).equals("b")
|
||||
})
|
||||
o("catch can return undefined", function() {
|
||||
var stream = Stream.reject(new Error("b")).catch(function(e) {}).map(function(value) {return String(value)})
|
||||
|
||||
o(stream()).equals("undefined")
|
||||
o(stream.error()).equals(undefined)
|
||||
})
|
||||
o("catch does not prevent sibling error propagation", function() {
|
||||
var a = Stream.reject(new Error("a"))
|
||||
var b = a.map(function(value) {return value + "b"}).catch(function(e) {})
|
||||
var c = a.map(function(value) {return value + "c"})
|
||||
var d = Stream.combine(function(b, c) {return b() + c()}, [b, c])
|
||||
|
||||
o(d()).equals(undefined)
|
||||
o(d.error().message).equals("a")
|
||||
})
|
||||
o("catches absorbed rejected stream", function() {
|
||||
var caught
|
||||
var stream = Stream.stream(1).map(function() {
|
||||
return Stream.reject(new Error("error"))
|
||||
}).catch(function(value) {
|
||||
caught = value
|
||||
return "no" + value.message
|
||||
}).map(function(value) {
|
||||
return value + "mapped"
|
||||
})
|
||||
|
||||
o(stream()).equals("noerrormapped")
|
||||
})
|
||||
})
|
||||
o.spec("map", function() {
|
||||
o("works", function() {
|
||||
var stream = Stream.stream()
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
|
||||
stream(3)
|
||||
|
||||
o(doubled()).equals(6)
|
||||
})
|
||||
o("works with default value", function() {
|
||||
var stream = Stream.stream(3)
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
|
||||
o(doubled()).equals(6)
|
||||
})
|
||||
o("works with undefined value", function() {
|
||||
var stream = Stream.stream()
|
||||
var mapped = stream.map(function(value) {return String(value)})
|
||||
|
||||
stream(undefined)
|
||||
|
||||
o(mapped()).equals("undefined")
|
||||
})
|
||||
o("works with default undefined value", function() {
|
||||
var stream = Stream.stream(undefined)
|
||||
var mapped = stream.map(function(value) {return String(value)})
|
||||
|
||||
o(mapped()).equals("undefined")
|
||||
})
|
||||
})
|
||||
o.spec("ap", function() {
|
||||
o("works", function() {
|
||||
var apply = Stream.stream(function(value) {return value * 2})
|
||||
var stream = Stream.stream(3)
|
||||
var applied = apply.ap(stream)
|
||||
|
||||
o(applied()).equals(6)
|
||||
|
||||
apply(function(value) {return value / 3})
|
||||
|
||||
o(applied()).equals(1)
|
||||
|
||||
stream(9)
|
||||
|
||||
o(applied()).equals(3)
|
||||
})
|
||||
o("works with undefined value", function() {
|
||||
var apply = Stream.stream(function(value) {return String(value)})
|
||||
var stream = Stream.stream(undefined)
|
||||
var applied = apply.ap(stream)
|
||||
|
||||
o(applied()).equals("undefined")
|
||||
|
||||
apply(function(value) {return String(value) + "a"})
|
||||
|
||||
o(applied()).equals("undefineda")
|
||||
})
|
||||
})
|
||||
o.spec("absorbing semantics", function() {
|
||||
o("absorbs stream", function() {
|
||||
var stream = Stream.stream(Stream.stream(1))
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
|
||||
o(stream()).equals(1)
|
||||
o(doubled()).equals(2)
|
||||
})
|
||||
o("absorbs stream on update", function() {
|
||||
var stream = Stream.stream()
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
|
||||
stream(Stream.stream(1))
|
||||
|
||||
o(stream()).equals(1)
|
||||
o(doubled()).equals(2)
|
||||
})
|
||||
o("absorbs errored stream", function() {
|
||||
var stream = Stream.stream(Stream.reject(1))
|
||||
var doubled = stream.error.map(function(value) {return value * 2})
|
||||
|
||||
o(stream()).equals(undefined)
|
||||
o(stream.error()).equals(1)
|
||||
o(doubled()).equals(2)
|
||||
})
|
||||
o("absorbs pending stream", function() {
|
||||
var count = 0
|
||||
var stream = Stream.stream(Stream.stream())
|
||||
var mapped = stream.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
o(stream()).equals(undefined)
|
||||
o(count).equals(0)
|
||||
})
|
||||
o("absorbs ended stream", function() {
|
||||
var count = 0
|
||||
var ended = Stream.stream()
|
||||
ended.end(true)
|
||||
|
||||
var stream = Stream.stream(ended)
|
||||
var mapped = stream.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
stream(1)
|
||||
|
||||
o(count).equals(0)
|
||||
})
|
||||
o("combine absorbs stream", function() {
|
||||
var stream = Stream.stream(1)
|
||||
var combined = Stream.combine(function(stream) {
|
||||
return Stream.stream(2)
|
||||
}, [stream])
|
||||
var doubled = combined.map(function(value) {return value * 2})
|
||||
|
||||
o(combined()).equals(2)
|
||||
o(doubled()).equals(4)
|
||||
})
|
||||
o("combine absorbs errored stream", function() {
|
||||
var stream = Stream.stream(1)
|
||||
var combined = Stream.combine(function(stream) {
|
||||
return Stream.reject(2)
|
||||
}, [stream])
|
||||
var doubled = combined.error.map(function(value) {return value * 2})
|
||||
|
||||
o(combined()).equals(undefined)
|
||||
o(combined.error()).equals(2)
|
||||
o(doubled()).equals(4)
|
||||
})
|
||||
o("combine absorbs pending stream", function() {
|
||||
var count = 0
|
||||
var stream = Stream.stream(1)
|
||||
var combined = Stream.combine(function(stream) {
|
||||
return Stream.stream()
|
||||
}, [stream])
|
||||
var mapped = combined.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
o(combined()).equals(undefined)
|
||||
o(count).equals(0)
|
||||
})
|
||||
o("combine absorbs ended stream", function() {
|
||||
var count = 0
|
||||
var stream = Stream.stream(1)
|
||||
var combined = Stream.combine(function(stream) {
|
||||
var ended = Stream.stream(2)
|
||||
ended.end(true)
|
||||
return ended
|
||||
}, [stream])
|
||||
var mapped = combined.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
o(combined()).equals(2)
|
||||
o(count).equals(0)
|
||||
})
|
||||
o("reject absorbs stream", function() {
|
||||
var stream = Stream.reject(Stream.stream(1))
|
||||
var doubled = stream.error.map(function(value) {return value * 2})
|
||||
|
||||
o(stream.error()).equals(1)
|
||||
o(doubled()).equals(2)
|
||||
})
|
||||
o("reject absorbs errored stream", function() {
|
||||
var count = 0
|
||||
var stream = Stream.reject(Stream.reject(new Error("error")))
|
||||
var mapped = stream.error.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
o(stream.error().message).equals("error")
|
||||
o(count).equals(1)
|
||||
})
|
||||
o("reject absorbs pending stream", function() {
|
||||
var count = 0
|
||||
var stream = Stream.reject(Stream.stream())
|
||||
var mapped = stream.error.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
o(stream.error()).equals(undefined)
|
||||
o(count).equals(0)
|
||||
})
|
||||
o("reject absorbs ended stream", function() {
|
||||
var count = 0
|
||||
var ended = Stream.stream(1)
|
||||
ended.end(true)
|
||||
|
||||
var stream = Stream.reject(ended)
|
||||
var mapped = stream.error.map(function() {
|
||||
count++
|
||||
})
|
||||
|
||||
o(count).equals(0)
|
||||
})
|
||||
o("ended stream absorbs stream", function() {
|
||||
var stream = Stream.stream()
|
||||
stream.end(true)
|
||||
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
stream(Stream.stream(1))
|
||||
|
||||
o(stream()).equals(1)
|
||||
o(doubled()).equals(undefined)
|
||||
})
|
||||
o("ended stream absorbs pending stream", function() {
|
||||
var stream = Stream.stream()
|
||||
stream.end(true)
|
||||
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
stream(Stream.stream())
|
||||
|
||||
o(stream()).equals(undefined)
|
||||
o(doubled()).equals(undefined)
|
||||
})
|
||||
o("ended stream absorbs errored stream", function() {
|
||||
var stream = Stream.stream()
|
||||
stream.end(true)
|
||||
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
stream(Stream.reject(new Error("error")))
|
||||
|
||||
o(stream.error().message).equals("error")
|
||||
o(doubled()).equals(undefined)
|
||||
})
|
||||
o("ended stream absorbs ended stream", function() {
|
||||
var stream = Stream.stream(1)
|
||||
stream.end(true)
|
||||
|
||||
var ended = Stream.stream(2)
|
||||
ended.end(true)
|
||||
|
||||
var doubled = stream.map(function(value) {return value * 2})
|
||||
stream(ended)
|
||||
|
||||
o(stream()).equals(2)
|
||||
o(doubled()).equals(undefined)
|
||||
})
|
||||
})
|
||||
o.spec("fantasy-land", function() {
|
||||
o.spec("functor", function() {
|
||||
o("identity", function() {
|
||||
var stream = Stream.stream(3)
|
||||
var mapped = stream.map(function(value) {return value})
|
||||
|
||||
o(stream()).equals(mapped())
|
||||
})
|
||||
o("composition", function() {
|
||||
function f(x) {return x * 2}
|
||||
function g(x) {return x * x}
|
||||
|
||||
var stream = Stream.stream(3)
|
||||
|
||||
var mapped = stream.map(function(value) {return f(g(value))})
|
||||
var composed = stream.map(g).map(f)
|
||||
|
||||
o(mapped()).equals(18)
|
||||
o(mapped()).equals(composed())
|
||||
})
|
||||
})
|
||||
o.spec("apply", function() {
|
||||
o("composition", function() {
|
||||
var a = Stream.stream(function(value) {return value * 2})
|
||||
var u = Stream.stream(function(value) {return value * 3})
|
||||
var v = Stream.stream(5)
|
||||
|
||||
var mapped = a.map(function(f) {
|
||||
return function(g) {
|
||||
return function(x) {
|
||||
return f(g(x))
|
||||
}
|
||||
}
|
||||
}).ap(u).ap(v)
|
||||
|
||||
var composed = a.ap(u.ap(v))
|
||||
|
||||
o(mapped()).equals(30)
|
||||
o(mapped()).equals(composed())
|
||||
})
|
||||
})
|
||||
o.spec("applicative", function() {
|
||||
o("identity", function() {
|
||||
var a = Stream.stream().of(function(value) {return value})
|
||||
var v = Stream.stream(5)
|
||||
|
||||
o(a.ap(v)()).equals(5)
|
||||
o(a.ap(v)()).equals(v())
|
||||
})
|
||||
o("homomorphism", function() {
|
||||
var a = Stream.stream(0)
|
||||
var f = function(value) {return value * 2}
|
||||
var x = 3
|
||||
|
||||
o(a.of(f).ap(a.of(x))()).equals(6)
|
||||
o(a.of(f).ap(a.of(x))()).equals(a.of(f(x))())
|
||||
})
|
||||
o("interchange", function() {
|
||||
var u = Stream.stream(function(value) {return value * 2})
|
||||
var a = Stream.stream()
|
||||
var y = 3
|
||||
|
||||
o(u.ap(a.of(y))()).equals(6)
|
||||
o(u.ap(a.of(y))()).equals(a.of(function(f) {return f(y)}).ap(u)())
|
||||
})
|
||||
})
|
||||
})
|
||||
})
|
||||
Loading…
Add table
Add a link
Reference in a new issue