refactor: Move scan and scanMerge to stream module (#1718)

stream/scan.js

@@ -1,13 +0,0 @@
-"use strict"
-
-var combine = require("./stream").combine
-
-module.exports = function (reducer, seed, stream) {
-	var newStream = combine(function (s) {
-		return seed = reducer(seed, s._state.value)
-	}, [stream])
-
-	if (newStream._state.state === 0) newStream(seed)
-
-	return newStream
-}

stream/scanMerge.js

@@ -1,25 +0,0 @@
-"use strict"
-
-var combine = require("./stream").combine
-
-module.exports = function(tuples, seed) {
-	var streams = tuples.map(function(tuple) {
-		var stream = tuple[0]
-		if (stream._state.state === 0) stream(undefined)
-		return stream
-	})
-
-	var newStream = combine(function() {
-		var changed = arguments[arguments.length - 1]
-
-		streams.forEach(function(stream, idx) {
-			if (changed.indexOf(stream) > -1) {
-				seed = tuples[idx][1](seed, stream._state.value)
-			}
-		})
-
-		return seed
-	}, streams)
-
-	return newStream
-}

stream/stream.js

@@ -109,13 +109,48 @@ function merge(streams) {
 		return streams.map(function(s) {return s()})
 	}, streams)
 }
+
+function scan(reducer, seed, stream) {
+	var newStream = combine(function (s) {
+		return seed = reducer(seed, s._state.value)
+	}, [stream])
+
+	if (newStream._state.state === 0) newStream(seed)
+
+	return newStream
+}
+
+function scanMerge(tuples, seed) {
+	var streams = tuples.map(function(tuple) {
+		var stream = tuple[0]
+		if (stream._state.state === 0) stream(undefined)
+		return stream
+	})
+
+	var newStream = combine(function() {
+		var changed = arguments[arguments.length - 1]
+
+		streams.forEach(function(stream, idx) {
+			if (changed.indexOf(stream) > -1) {
+				seed = tuples[idx][1](seed, stream._state.value)
+			}
+		})
+
+		return seed
+	}, streams)
+
+	return newStream
+}
+
 createStream["fantasy-land/of"] = createStream
 createStream.merge = merge
 createStream.combine = combine
+createStream.scan = scan
+createStream.scanMerge = scanMerge
 createStream.HALT = HALT
 
 if (typeof module !== "undefined") module["exports"] = createStream
 else if (typeof window.m === "function" && !("stream" in window.m)) window.m.stream = createStream
 else window.m = {stream : createStream}
 
-}());
+}());

stream/tests/test-scan.js

@@ -2,12 +2,11 @@
 
 var o = require("../../ospec/ospec")
 var stream = require("../stream")
-var scan = require("../scan")
 
 o.spec("scan", function() {
 	o("defaults to seed", function() {
 		var parent = stream()
-		var child = scan(function(out, p) {
+		var child = stream.scan(function(out, p) {
 			return out - p
 		}, 123, parent)
 		o(child()).equals(123)
@@ -15,7 +14,7 @@ o.spec("scan", function() {
 
 	o("accumulates values as expected", function() {
 		var parent = stream()
-		var child = scan(function(arr, p) {
+		var child = stream.scan(function(arr, p) {
 			return arr.concat(p)
 		}, [], parent)
 

stream/tests/test-scanMerge.js

@@ -2,14 +2,13 @@
 
 var o = require("../../ospec/ospec")
 var stream = require("../stream")
-var scanMerge = require("../scanMerge")
 
 o.spec("scanMerge", function() {
 	o("defaults to seed", function() {
 		var parent1 = stream()
 		var parent2 = stream()
 
-		var child = scanMerge([
+		var child = stream.scanMerge([
 			[parent1, function(out, p1) {
 				return out + p1
 			}],
@@ -25,7 +24,7 @@ o.spec("scanMerge", function() {
 		var parent1 = stream()
 		var parent2 = stream()
 
-		var child = scanMerge([
+		var child = stream.scanMerge([
 			[parent1, function(out, p1) {
 				return out + p1
 			}],