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Matt McKegg / mutant



Tree: 70bdc654bff8ac23d9006bcbee7a5fa93d8abf62

Files: 70bdc654bff8ac23d9006bcbee7a5fa93d8abf62 / lookup.js

1915 bytesRaw
1var MutantMap = require('./map')
2var computed = require('./computed')
3var resolve = require('./resolve')
4var KeyValue = require('./lib/key-value')
5var isObservable = require('./is-observable')
6
7module.exports = Lookup
8
9function Lookup (obs, lambdaOrKey, opts) {
10 var mapped = MutantMap(obs, function (item, invalidateOn) {
11 if (typeof lambdaOrKey === 'function') {
12 var value = lambdaOrKey(item, invalidateOn)
13 if (isObservable(value) && value._type === 'MutantKeyValue') {
14 return value // passthru
15 } else if (Array.isArray(value)) {
16 return KeyValue(value[0], value[1])
17 } else if (value != null) {
18 return KeyValue(value, item)
19 }
20 } else if (typeof lambdaOrKey === 'string') {
21 return KeyValue(item[lambdaOrKey], item)
22 }
23 })
24
25 var raw = {}
26 var value = {}
27 var keys = new Set()
28
29 var instance = computed.extended(mapped, function update () {
30 var currentKeys = []
31
32 for (var i = 0; i < mapped.getLength(); i++) {
33 var item = mapped.get(i)
34 if (item) {
35 var key = resolve(item.key)
36 if (key != null) {
37 var rawValue = item.value
38 currentKeys.push(key)
39 keys.add(key)
40 raw[key] = rawValue
41 value[key] = resolve(rawValue)
42 }
43 }
44 }
45
46 // remove deleted keys
47 Array.from(keys.values()).filter(function (k) {
48 return !currentKeys.includes(k)
49 }).forEach(function (key) {
50 keys.delete(key)
51 delete raw[key]
52 delete value[key]
53 })
54
55 return value
56 })
57
58 var result = function MutantLookup (listener) {
59 return instance(listener)
60 }
61
62 result.keys = function () {
63 instance.checkUpdated()
64 return Array.from(keys.values())
65 }
66
67 result.get = function (key) {
68 instance.checkUpdated()
69 return raw[key]
70 }
71
72 result.has = function (key) {
73 instance.checkUpdated()
74 return key in raw
75 }
76
77 return result
78}
79

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