Completed untested versions of playlist and playlist song classes.

Restructured for improved development and deployment pipeline.

Added webpack and configurations for development and production.

Began adding JSDocs.

Added eslint.

.eslintrc.json

@@ -0,0 +1,35 @@
+{
+    "env": {
+        "browser": true,
+        "es2021": true
+    },
+    "extends": [
+        "eslint:recommended",
+        "plugin:jsdoc/recommended"
+    ],
+    "parserOptions": {
+        "ecmaVersion": "latest",
+        "sourceType": "module"
+    },
+    "plugins": [
+        "jsdoc"
+    ],
+    "rules": {
+        "indent": [
+            "error",
+            4
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "double"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ]
+    }
+}

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "cSpell.words": [
+        "linebreak"
+    ]
+}

server/package.json

@@ -9,7 +9,14 @@
   },
   "author": "",
   "license": "ISC",
-  "dependencies": {
-    "express": "^4.17.3"
+  "devDependencies": {
+    "css-loader": "^6.7.1",
+    "eslint": "^8.13.0",
+    "eslint-plugin-jsdoc": "^39.2.1",
+    "style-loader": "^3.3.1",
+    "webpack": "^5.72.0",
+    "webpack-cli": "^4.9.2",
+    "webpack-dev-server": "^4.8.1",
+    "webpack-merge": "^5.8.0"
   }
-}
+}

src/VisualizerCore.js

@@ -1 +1,52 @@
-// TODO: Reorganize such that audioshowkit.js uses VisualizerCore.js.
+export default class VisualizerCore {
+    constructor(mediaSource, fftSize = 1024) {
+        this._stream = mediaSource;
+        this._analyzing = false;
+        this._updateListeners = [];
+        this._audioCtx = new window.AudioContext();
+        if (mediaSource instanceof HTMLMediaElement) {
+            this._source = this._audioCtx.createMediaElementSource(this._stream);
+        } else {
+            this._source = this._audioCtx.createMediaStreamSource(this._stream);
+        }
+        this._analyzer = this._audioCtx.createAnalyser();
+        this._analyzer.fftSize = fftSize;
+        this._source.connect(this._analyzer);
+        this._analyzer.connect(this._audioCtx.destination);
+        this._buffer = new Uint8Array(this._analyzer.frequencyBinCount);
+
+        this.lastUpdate = null;
+    }
+
+    analyze() {
+        if (this._analyzing) {
+            return;
+        }
+        this._analyzing = true;
+        let self = this; // since calling from requestAnimationFrame means "this" is no longer set to produced object.
+        requestAnimationFrame((timestamp) => {
+            if (!self._analyzing) return;
+
+            requestAnimationFrame(self.update);
+            if (!self.lastUpdate) {
+                self.lastUpdate = timestamp;
+            }
+            let delta = timestamp - self.lastUpdate;
+            self._analyzer.getByteFrequencyData(self._buffer);
+
+            self._updateListeners.forEach(listener => {
+                listener(delta, self._buffer);
+            });
+        });
+    }
+
+    stop() {
+        this._analyzing = false;
+    }
+    addUpdateListener(listener) {
+        this._updateListeners.push(listener);
+    }
+    getNumberOfBins() {
+        return this._buffer.length;
+    }
+}

src/audioshowkit.js

@@ -1,54 +1,4 @@
 "use strict";
 
-function VisualizerCore(mediaSource, fftSize = 1024) {
-    this._stream = mediaSource;
-    this._analyzing = false;
-    this._updateListeners = [];
-    this._audioCtx = new window.AudioContext();
-    this._source = null; // Prepare for either a MediaStream or a MediaElement.
-    try {
-        this.source = this._audioCtx.createMediaStreamSource(this._stream);
-    } catch (e) {
-        this._source = this._audioCtx.createMediaElementSource(this._stream);
-    }
-    this._analyzer = this._audioCtx.createAnalyser();
-    this._analyzer.fftSize = fftSize;
-    this._source.connect(this._analyzer);
-    this._analyzer.connect(this._audioCtx.destination);
-    this._buffer = new Uint8Array(this._analyzer.frequencyBinCount);
-
-    this.lastUpdate = null;
-
-    this.analyze = function () {
-        if (this._analyzing) {
-            return;
-        }
-        this._analyzing = true;
-        requestAnimationFrame(this.update);
-    };
-
-    let vcore = this; // since calling from requestAnimationFrame means "this" is no longer set to produced object.
-    this.update = function (timestamp) {
-        if (!vcore._analyzing) return;
-
-        requestAnimationFrame(vcore.update);
-        if (!vcore.lastUpdate) {
-            vcore.lastUpdate = timestamp;
-        }
-        let delta = timestamp - vcore.lastUpdate;
-        vcore._analyzer.getByteFrequencyData(vcore._buffer);
-
-        vcore._updateListeners.forEach(listener => {
-            listener(delta, vcore._buffer);
-        });
-    };
-    this.stop = function () {
-        this._analyzing = false;
-    };
-    this.addUpdateListener = function (listener) {
-        this._updateListeners.push(listener);
-    };
-    this.getNumberOfBins = function () {
-        return this._buffer.length;
-    };
-}
+// TODO: Detect annotated elements.
+// TODO: Set up global scoping.

src/player/PlayButton.js

@@ -0,0 +1,6 @@
+export default class PlayButton {
+
+    constructor() {
+
+    }
+}

src/player/PlaylistSong.js

@@ -1,26 +1,165 @@
-export default function PlaylistSong(url, name, author, playlist) {
-    this._displayName = name;
-    this._author = author;
-    this._url = url;
-    this._mediaStream = null;
-    this._playlist = playlist;
+import SongPlaylist from "./SongPlaylist";
 
-    this.getAudio = function () {
-        if (this.mediaStream) {
-            return this.mediaStream;
+/**
+ * A song with metadata that can be used as part of a {@link SongPlaylist}.
+ */
+export default class PlayListSong {
+
+    /**
+     * Constructs a song for a {@link SongPlaylist}.
+     * 
+     * @param {string} url the url to fetch the song from.
+     * @param {string} name the name of the song.
+     * @param {string} author the author of the song.
+     * @param {SongPlaylist} playlist the {@link SongPlaylist} this song is part of.
+     */
+    constructor(url, name, author, playlist) {
+        this._displayName = name;
+        this._author = author;
+        this._url = url;
+        this._audio = null;
+        this._playlist = playlist;
+
+        /**
+         * Whether or not this song is ready to be played.
+         */
+        this.ready = false;
+    }
+
+    /**
+     * @callback AudioEventCallback
+     * @param {HTMLAudioElement} audio
+     */
+
+    /**
+     * 
+     * @param {AudioEventCallback} [onReady] called when the song is ready, including right away if the song is already ready.
+     * @returns {HTMLAudioElement} The audio element that represents this song.
+     */
+    getAudio(onReady) {
+        if (this._audio) {
+            if (this.ready) {
+                if (onReady) onReady(this._audio);
+                return this._audio;
+            }
+            return this._audio;
         }
-        this.mediaStream = new Audio(url);
-    };
-    this.getDisplayName = function () {
+        this._audio = new Audio(this._url);
+
+        this._audio.addEventListener("canplaythrough", () => {
+            this.ready = true;
+            if (onReady) {
+                onReady(this._audio);
+            }
+        });
+        return this._audio;
+    }
+
+    /**
+     * 
+     * @returns {string} representing the name of the song to be displayed.
+     */
+    getDisplayName = function () {
         return this._displayName;
     };
-    this.getAuthor = function () {
+
+    /**
+     * 
+     * @returns {string} representing the author of the song.
+     */
+    getAuthor = function () {
         return this._getAuthor;
     };
-    this.getUrl = function () {
+
+    /**
+     * 
+     * @returns {string} representing the url at which the file for this song can be found.
+     */
+    getUrl = function () {
         return this._url;
     };
-    this.getPlaylist = function () {
+
+    /**
+     * 
+     * @returns {SongPlaylist} the playlist this song is part of.
+     */
+    getPlaylist = function () {
         return this._playlist;
     };
+
+    /**
+     * 
+     * @returns {boolean} true if and only if there is audio data that is either already loaded or is being loaded.
+     */
+    audioInstantiated() {
+        return this._audio ? true : false;
+    }
+
+    /**
+     * Begins audio playback as soon as possible.
+     */
+    play() {
+        this.getAudio((audio) => {
+            audio.play();
+        });
+    }
+
+    /**
+     * Pauses the audio playback, unless the audio data has yet to be instantiated.
+     */
+    pause() {
+        if (!this.audioInstantiated()) return;
+        this.getAudio((audio) => {
+            audio.pause();
+        });
+    }
+
+    /**
+     * 
+     * @returns {number} the volume on a scale of 0 to 1.
+     */
+    getVolume() {
+        return this.getAudio().volume;
+    }
+
+    /**
+     * 
+     * @param {number} volume a normalized volume on a scale of 0 to 1.
+     */
+    setVolume(volume) {
+        this.getAudio().volume = volume;
+    }
+    /**
+     * 
+     * @returns {number} the number of seconds into the song.
+     */
+    getCurrentTime() {
+        return this.getAudio().currentTime;
+    }
+
+    /**
+     * 
+     * @param {number} currentTime the time position in the song to jump to in seconds.
+     */
+    setCurrentTime(currentTime) {
+        this.getAudio().currentTime = currentTime;
+    }
+
+    /**
+     * 
+     * @returns {number} the duration of the song.
+     */
+    getDuration() {
+        return this.getAudio().duration;
+    }
+
+    /**
+     * Unloads the audio data.
+     */
+    unloadAudio() {
+        if (!this.audioInstantiated()) return;
+        this._audio.pause();
+        this._audio = null;
+        this.ready = false;
+    }
 }

src/player/SongPlaylist.js

@@ -0,0 +1,78 @@
+import PlaylistSong from "./PlaylistSong";
+
+/**
+ * A playlist that holds a multitude of songs.
+ */
+export default class SongPlaylist {
+
+    /**
+     * Instantiates a playlist for songs.
+     * 
+     * @param {string} name The name of the playlist.
+     */
+    constructor(name) {
+        this._list = [];
+        this._name = name;
+        this._current = 0;
+    }
+
+    /**
+     * 
+     * @returns {string} the name of the string.
+     */
+    getName() {
+        return this._name;
+    }
+
+    /**
+     * 
+     * @param {number} index the index of the song to retrieve.
+     * @returns {PlaylistSong} the song at the given index.
+     */
+    songAtIndex(index) {
+        if (index >= this._list.length) {
+            return null;
+        }
+        return this.list[index];
+    }
+
+    songsWithName(name) {
+        return this._list.filter((item) => item.getDisplayName() == name);
+    }
+
+    add(url, name, author) {
+        this._list.push(new PlaylistSong(url, name, author, this, this._list.length));
+    }
+
+    remove(index) {
+        if (index >= this._list.length) {
+            return null;
+        }
+        let removed = this._list.splice(index, 1);
+        if (removed.length > 0) {
+            return removed[0];
+        }
+    }
+
+    findSongIndex(name) {
+        // TODO: Could probably be optimized.
+        return this._list.findIndex((item) => item.getDisplayName() == name);
+    }
+
+    /**
+     * 
+     * @returns {number} total number of songs in this playlist.
+     */
+    total() {
+        return this._list.length;
+    }
+
+    /**
+     * Unloads the audio data of all songs in this playlist.
+     */
+    unloadAllAudio() {
+        this._list.forEach(playlistSong => {
+            playlistSong.unloadAudio();
+        });
+    }
+}

webpack.common.js

@@ -0,0 +1,21 @@
+export default {
+    entry: {
+        audioshowkit: "./src/audioshowkit.js"
+    },
+    module: {
+        rules: [
+            {
+                test: /\.html$/i,
+                loader: "html-loader",
+            },
+            {
+                test: /\.css$/i,
+                use: ['style-loader', 'css-loader'],
+            }
+        ]
+    },
+    output: {
+        filename: "[name].js",
+        path: "./dist"
+    }
+};

webpack.dev.js

@@ -0,0 +1,13 @@
+import merge from "webpack-merge";
+import webpackCommon from "./webpack.common";
+
+devConfig = {
+    mode: "development",
+    devtools: "inline-source-map",
+
+    devServer: {
+        static: "./dist"
+    }
+}
+
+export default merge(webpackCommon, devConfig);

webpack.prod.js

@@ -0,0 +1,12 @@
+import merge from "webpack-merge"
+import webpackCommon from "./webpack.common"
+
+prodConfig = {
+    mode: "production",
+    output: {
+        filename: "[name].js",
+        path: "./public"
+    }
+}
+
+export default merge(webpackCommon, prodConfig);