refact(store): use fp transformations

package-lock.json

@@ -6293,8 +6293,7 @@
     "lodash": {
       "version": "4.17.15",
       "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.15.tgz",
-      "integrity": "sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A==",
-      "dev": true
+      "integrity": "sha512-8xOcRHvCjnocdS5cpwXQXVzmmh5e5+saE2QGoeQmbKmRS6J3VQppPOIt0MnmE+4xlZoumy0GPG0D0MVIQbNA1A=="
     },
     "lodash.clone": {
       "version": "4.5.0",
@@ -8675,6 +8674,14 @@
       "integrity": "sha1-fRh9tcbNu9ZNdaMvkbiZi94yc8M=",
       "dev": true
     },
+    "svelte-pipeable-store": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/svelte-pipeable-store/-/svelte-pipeable-store-1.0.3.tgz",
+      "integrity": "sha512-VmsVQHPPASqTls53uT0HszKbdn6FTJLdwQvHPA1AJU1U2POYoGnG36+zK0tQzF9F/DHeR2ufvoHV2ozqDiaJ4w==",
+      "requires": {
+        "lodash": "^4.17.15"
+      }
+    },
     "svelte-routing": {
       "version": "1.4.0",
       "resolved": "https://registry.npmjs.org/svelte-routing/-/svelte-routing-1.4.0.tgz",

package.json

@@ -28,6 +28,7 @@
     "get-urls": "^9.2.0",
     "iter-tools": "^7.0.0-rc.0",
     "route-parser": "0.0.5",
+    "svelte-pipeable-store": "^1.0.3",
     "svelte-routing": "^1.4.0"
   },
   "browserslist": [

src/components/Queue.svelte

@@ -6,10 +6,14 @@
             <div class="title">{$next.title}</div>
             <div class="user">shared by {$next.referer.username} <DistanceDate date={$next.date} /></div>
         </div>
+    {:else}
+        NO NEXT TRACK
     {/if}
 
+
+
     {#if $enqueueing}
-        LOADING NEXT
+        ENQUEING
     {/if}
 
 

src/components/Radio.svelte

@@ -17,79 +17,16 @@
 </div>
 
 <script>
-    import { onMount, onDestroy } from 'svelte'
-    import { derived, get } from 'svelte/store'
-
     import Header from '/components/layout/Header.svelte'
     import Footer from '/components/layout/Footer.svelte'
     import Queue from '/components/Queue.svelte'
     import Viewer from '/components/Viewer.svelte'
-    import { radioIterator, radioShareIterator } from '/services/radio.js'
-    import { fetchStatus } from '/services/mastodon.js'
 
-    import { domain, hashtags, queue, next, current, enqueueing, select } from '/store.js'
-    import DeepSet from '/services/deep-set.js'
+    import { queue, next, current, select } from '/store.js'
 
     export let share
 
-    const cache = new DeepSet()
-
-    let nextUnsubcribe = null
-    let currentUnsubcribe = null
-
-    onMount(async () => {
-        let iterator
-
-        if (share != null) {
-            const track = await fetchStatus(share.domain, share.id)
-            iterator = radioShareIterator(track, get(domain), get(hashtags), cache)
-        } else {
-            iterator = radioIterator(get(domain), get(hashtags), cache)
+    $: if ($queue.length === 1 && $next != null && $current == null) {
+        select($next)
     }
-
-        // generated multiples times cannot usable and don't free resources
-        // const iterator = derived([domain, hashtags], ([$domain, $hashtags]) => radioIterator($domain, $hashtags))
-
-        const { value: first } = await iterator.next()
-
-        queue.set([first])
-        select(first)
-
-        nextUnsubcribe = next.subscribe(async nextValue => {
-            if (nextValue === null) {
-                if (!get(enqueueing)) {
-                    enqueueing.set(true)
-
-                    const { value: newTrack } = await iterator.next()
-
-                    if (newTrack) {
-                        queue.update(queueValue => [...queueValue, newTrack])
-                        next.set(newTrack)
-                    }
-
-                    enqueueing.set(false)
-                }
-            }
-        })
-
-        currentUnsubcribe = current.subscribe(currentValue => {
-            if (currentValue !== null) {
-                next.update(nextValue => {
-                    if (nextValue === currentValue) {
-                        return null
-                    } else {
-                        return nextValue
-                    }
-                })
-            }
-        })
-    })
-
-    onDestroy(() => {
-        for (const unsubcribe of [nextUnsubcribe, currentUnsubcribe]) {
-            if (unsubcribe) {
-                unsubcribe()
-            }
-        }
-    })
 </script>

src/services/store.js

@@ -0,0 +1,26 @@
+import { writable, readable } from 'svelte-pipeable-store'
+
+export { get } from 'svelte/store'
+export * from 'svelte-pipeable-store'
+
+export const writableLocalStorage = (key, value) => {
+    const item = JSON.parse(localStorage.getItem(key))
+    const store = writable(item === null ? value : item)
+
+    store.subscribe(x => localStorage.setItem(key, JSON.stringify(x)))
+
+    return store
+}
+
+export const distinct = () => {
+    return ({ subscribe }) => readable(undefined, set => {
+        let last
+
+        return subscribe(v => {
+            if (last !== v) {
+                set(v)
+                last = v
+            }
+        })
+    })
+}

src/services/svelte.js

@@ -1,10 +0,0 @@
-import { writable } from 'svelte/store'
-
-export const writableLocalStorage = (key, value) => {
-    const item = JSON.parse(localStorage.getItem(key))
-    const store = writable(item === null ? value : item)
-
-    store.subscribe(x => localStorage.setItem(key, JSON.stringify(x)))
-
-    return store
-}

src/store.js

@@ -1,5 +1,10 @@
-import { writable, derived, get } from 'svelte/store'
-import { writableLocalStorage } from '/services/svelte.js'
+import { get, writable, derived, scan, wait, startWith, writableLocalStorage } from '/services/store.js'
+import { radioIterator, radioShareIterator } from '/services/radio.js'
+import DeepSet from '/services/deep-set.js'
+import { distinct } from './services/store'
+
+
+const cache = new DeepSet()
 
 export const domain = writableLocalStorage('domain', 'eldritch.cafe')
 
@@ -14,11 +19,44 @@ export const paused = writable(true)
 export const muted = writableLocalStorage('muted', false)
 export const volume = writableLocalStorage('volume', 100)
 
-export const queue = writable([])
-export const next = writable(null)
 export const current = writable(null)
 export const enqueueing = writable(false)
 
+
+export const iterator = derived([domain, hashtags], ([$domain, $hashtags], set) => {
+    const iterator = radioIterator($domain, $hashtags, cache)
+    set(iterator)
+
+    return () => {
+        iterator.return()
+    }
+}, null)
+
+
+export const next = derived([iterator, current], ([$iterator, $current]) => ({ $iterator, $current }))
+    .pipe(scan(($nextPromise, { $iterator, $current }) => {
+        return $nextPromise.then($next => {
+            if ($next == null || $next === $current) {
+                enqueueing.set(true)
+                return $iterator.next().then(({ done, value }) => {
+                    enqueueing.set(false)
+                    return value
+                })
+            } else {
+                return $nextPromise
+            }
+        })
+    }, Promise.resolve(null)))
+    .pipe(wait(x => x))
+    // distinct but with strict check
+    .pipe(distinct())
+    .pipe(startWith(null))
+
+
+export const queue = next
+    .pipe(scan((a, x) => x == null ? a : [...a, x], []))
+
+
 export const loading = writable(false)
 
 const index = derived([queue, current], ([$queue, $current]) => {