23fe0a5ab1
* Fixed bad test for scan The previous test didn't catch the fact that the accumulator had been broke, it's value became the special value `SKIP`. * Fixed Stream.scan() to accept SKIP value * Update stream/stream.js Dropped unnecessary ternary as suggested by @isiahmeadows Co-Authored-By: gamb <adam@gamb.co>
67 lines
1.3 KiB
JavaScript
67 lines
1.3 KiB
JavaScript
"use strict"
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var o = require("../../ospec/ospec")
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var stream = require("../stream")
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o.spec("scan", function() {
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o("defaults to seed", function() {
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var parent = stream()
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var child = stream.scan(function(out, p) {
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return out - p
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}, 123, parent)
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o(child()).equals(123)
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})
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o("accumulates values as expected", function() {
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var parent = stream()
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var child = stream.scan(function(arr, p) {
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return arr.concat(p)
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}, [], parent)
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parent(7)
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parent("11")
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parent(undefined)
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parent({a: 1})
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var result = child()
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// deepEquals fails on arrays?
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o(result[0]).equals(7)
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o(result[1]).equals("11")
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o(result[2]).equals(undefined)
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o(result[3]).deepEquals({a: 1})
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})
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o("reducer can return SKIP to prevent child updates", function() {
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var count = 0
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var action = stream()
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var store = stream.scan(function (arr, value) {
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switch (typeof value) {
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case "number":
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return arr.concat(value)
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default:
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return stream.SKIP
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}
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}, [], action)
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var child = store.map(function (p) {
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count++
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return p
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})
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var result
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action(7)
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action("11")
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action(undefined)
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action({a: 1})
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action(8) // assures we didn't break the accumulator
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result = child()
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// check we got the expect result
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o(result[0]).equals(7)
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o(result[1]).equals(8)
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// check child received minimum # of updates
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o(count).equals(3)
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})
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})
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