Update syntax for eslint-config-scratch

src/ADPCMSoundDecoder.js

@@ -10,14 +10,13 @@ const log = require('./log');
  * https://github.com/LLK/scratch-flash/blob/master/src/sound/WAVFile.as
  * @constructor
  */
-function ADPCMSoundDecoder () {
+const ADPCMSoundDecoder = function () {};
-}
 
 /**
  * Decode an ADPCM sound stored in an ArrayBuffer and return a promise
  * with the decoded audio buffer.
  * @param  {ArrayBuffer} audioData - containing ADPCM encoded wav audio
- * @return {Tone.Buffer}
+ * @return {Tone.Buffer} the decoded audio buffer
  */
 ADPCMSoundDecoder.prototype.decode = function (audioData) {
 
@@ -25,18 +24,18 @@ ADPCMSoundDecoder.prototype.decode = function (audioData) {
         const stream = new ArrayBufferStream(audioData);
 
         const riffStr = stream.readUint8String(4);
-        if (riffStr != 'RIFF') {
+        if (riffStr !== 'RIFF') {
             log.warn('incorrect adpcm wav header');
             reject();
         }
 
         const lengthInHeader = stream.readInt32();
-        if ((lengthInHeader + 8) != audioData.byteLength) {
+        if ((lengthInHeader + 8) !== audioData.byteLength) {
             log.warn(`adpcm wav length in header: ${lengthInHeader} is incorrect`);
         }
 
         const wavStr = stream.readUint8String(4);
-        if (wavStr != 'WAVE') {
+        if (wavStr !== 'WAVE') {
             log.warn('incorrect adpcm wav header');
             reject();
         }
@@ -54,10 +53,10 @@ ADPCMSoundDecoder.prototype.decode = function (audioData) {
 
         const samples = this.imaDecompress(this.extractChunk('data', stream), this.adpcmBlockSize);
 
-        // todo: this line is the only place Tone is used here, should be possible to remove
+        // @todo this line is the only place Tone is used here, should be possible to remove
         const buffer = Tone.context.createBuffer(1, samples.length, this.samplesPerSecond);
 
-        // todo: optimize this? e.g. replace the divide by storing 1/32768 and multiply?
+        // @todo optimize this? e.g. replace the divide by storing 1/32768 and multiply?
         for (let i = 0; i < samples.length; i++) {
             buffer.getChannelData(0)[i] = samples[i] / 32768;
         }
@@ -97,12 +96,12 @@ ADPCMSoundDecoder.prototype.extractChunk = function (chunkType, stream) {
     while (stream.position < (stream.getLength() - 8)) {
         const typeStr = stream.readUint8String(4);
         const chunkSize = stream.readInt32();
-        if (typeStr == chunkType) {
+        if (typeStr === chunkType) {
             const chunk = stream.extract(chunkSize);
             return chunk;
         }
         stream.position += chunkSize;
-        
+
     }
 };
 
@@ -114,7 +113,10 @@ ADPCMSoundDecoder.prototype.extractChunk = function (chunkType, stream) {
  * @return {Int16Array} the uncompressed audio samples
  */
 ADPCMSoundDecoder.prototype.imaDecompress = function (compressedData, blockSize) {
-    let sample, step, code, delta;
+    let sample;
+    let step;
+    let code;
+    let delta;
     let index = 0;
     let lastByte = -1; // -1 indicates that there is no saved lastByte
     const out = [];
@@ -124,9 +126,9 @@ ADPCMSoundDecoder.prototype.imaDecompress = function (compressedData, blockSize)
 
     compressedData.position = 0;
     const a = 0;
-    while (a == 0) {
+    while (a === 0) {
-        if (((compressedData.position % blockSize) == 0) && (lastByte < 0)) { // read block header
+        if (((compressedData.position % blockSize) === 0) && (lastByte < 0)) { // read block header
-            if (compressedData.getBytesAvailable() == 0) break;
+            if (compressedData.getBytesAvailable() === 0) break;
             sample = compressedData.readInt16();
             index = compressedData.readUint8();
             compressedData.position++; // skip extra header byte
@@ -135,7 +137,7 @@ ADPCMSoundDecoder.prototype.imaDecompress = function (compressedData, blockSize)
         } else {
             // read 4-bit code and compute delta from previous sample
             if (lastByte < 0) {
-                if (compressedData.getBytesAvailable() == 0) break;
+                if (compressedData.getBytesAvailable() === 0) break;
                 lastByte = compressedData.readUint8();
                 code = lastByte & 0xF;
             } else {

src/ArrayBufferStream.js

@@ -8,10 +8,10 @@
  * @param {ArrayBuffer} arrayBuffer - array to use as a stream
  * @constructor
  */
-function ArrayBufferStream (arrayBuffer) {
+const ArrayBufferStream = function (arrayBuffer) {
     this.arrayBuffer = arrayBuffer;
     this.position = 0;
-}
+};
 
 /**
  * Return a new ArrayBufferStream that is a slice of the existing one
@@ -40,7 +40,7 @@ ArrayBufferStream.prototype.getBytesAvailable = function () {
 
 /**
  * Read an unsigned 8 bit integer from the stream
- * @return {number}
+ * @return {number} the next 8 bit integer in the stream
  */
 ArrayBufferStream.prototype.readUint8 = function () {
     const val = new Uint8Array(this.arrayBuffer, this.position, 1)[0];
@@ -52,7 +52,7 @@ ArrayBufferStream.prototype.readUint8 = function () {
  * Read a sequence of bytes of the given length and convert to a string.
  * This is a convenience method for use with short strings.
  * @param {number} length - the number of bytes to convert
- * @return {String} a String made by concatenating the chars in the input
+ * @return {string} a String made by concatenating the chars in the input
  */
 ArrayBufferStream.prototype.readUint8String = function (length) {
     const arr = new Uint8Array(this.arrayBuffer, this.position, length);
@@ -66,7 +66,7 @@ ArrayBufferStream.prototype.readUint8String = function (length) {
 
 /**
  * Read a 16 bit integer from the stream
- * @return {number}
+ * @return {number} the next 16 bit integer in the stream
  */
 ArrayBufferStream.prototype.readInt16 = function () {
     const val = new Int16Array(this.arrayBuffer, this.position, 1)[0];
@@ -76,7 +76,7 @@ ArrayBufferStream.prototype.readInt16 = function () {
 
 /**
  * Read an unsigned 16 bit integer from the stream
- * @return {number}
+ * @return {number} the next unsigned 16 bit integer in the stream
  */
 ArrayBufferStream.prototype.readUint16 = function () {
     const val = new Uint16Array(this.arrayBuffer, this.position, 1)[0];
@@ -86,7 +86,7 @@ ArrayBufferStream.prototype.readUint16 = function () {
 
 /**
  * Read a 32 bit integer from the stream
- * @return {number}
+ * @return {number} the next 32 bit integer in the stream
  */
 ArrayBufferStream.prototype.readInt32 = function () {
     const val = new Int32Array(this.arrayBuffer, this.position, 1)[0];
@@ -96,7 +96,7 @@ ArrayBufferStream.prototype.readInt32 = function () {
 
 /**
  * Read an unsigned 32 bit integer from the stream
- * @return {number}
+ * @return {number} the next unsigned 32 bit integer in the stream
  */
 ArrayBufferStream.prototype.readUint32 = function () {
     const val = new Uint32Array(this.arrayBuffer, this.position, 1)[0];

src/DrumPlayer.js

@@ -6,7 +6,7 @@ const Tone = require('tone');
  * @param {Tone.Gain} outputNode - a webAudio node that the drum sounds will send their output to
  * @constructor
  */
-function DrumPlayer (outputNode) {
+const DrumPlayer = function (outputNode) {
     this.outputNode = outputNode;
 
     const baseUrl = 'https://raw.githubusercontent.com/LLK/scratch-audio/develop/sound-files/drums/';
@@ -38,7 +38,7 @@ function DrumPlayer (outputNode) {
         this.drumSounds[i] = new SoundPlayer(this.outputNode);
         this.drumSounds[i].setBuffer(new Tone.Buffer(url));
     }
-}
+};
 
 /**
  * Play a drum sound.

src/InstrumentPlayer.js

@@ -12,7 +12,7 @@ const Soundfont = require('soundfont-player');
  * @param {Tone.Gain} outputNode - a webAudio node that the instrument will send its output to
  * @constructor
  */
-function InstrumentPlayer (outputNode) {
+const InstrumentPlayer = function (outputNode) {
     this.outputNode = outputNode;
 
     // Instrument names used by Musyng Kite soundfont, in order to
@@ -24,7 +24,7 @@ function InstrumentPlayer (outputNode) {
         'music_box', 'steel_drums', 'marimba', 'lead_1_square', 'fx_4_atmosphere'];
 
     this.instruments = [];
-}
+};
 
 /**
  * Play a note for some number of seconds with a particular instrument.
@@ -63,7 +63,7 @@ InstrumentPlayer.prototype.loadInstrument = function (instrumentNum) {
                 inst.connect(this.outputNode);
                 this.instruments[instrumentNum] = inst;
             });
-    
+
 };
 
 /**

src/SoundPlayer.js

@@ -5,13 +5,13 @@ const log = require('./log');
  * A SoundPlayer stores an audio buffer, and plays it
  * @constructor
  */
-function SoundPlayer () {
+const SoundPlayer = function () {
     this.outputNode = null;
     this.buffer = new Tone.Buffer();
     this.bufferSource = null;
     this.playbackRate = 1;
     this.isPlaying = false;
-}
+};
 
 /**
  * Connect the SoundPlayer to an output node
@@ -23,7 +23,7 @@ SoundPlayer.prototype.connect = function (node) {
 
 /**
  * Set an audio buffer
- * @param {Tone.Buffer} buffer
+ * @param {Tone.Buffer} buffer Buffer to set
  */
 SoundPlayer.prototype.setBuffer = function (buffer) {
     this.buffer = buffer;

src/effects/EchoEffect.js

@@ -8,7 +8,7 @@ const Tone = require('tone');
 * Clamped 0-100
 * @constructor
 */
-function EchoEffect () {
+const EchoEffect = function () {
     Tone.Effect.call(this);
 
     this.value = 0;
@@ -16,7 +16,7 @@ function EchoEffect () {
     this.delay = new Tone.FeedbackDelay(0.25, 0.5);
 
     this.effectSend.chain(this.delay, this.effectReturn);
-}
+};
 
 Tone.extend(EchoEffect, Tone.Effect);
 
@@ -30,7 +30,7 @@ EchoEffect.prototype.set = function (val) {
     this.value = this.clamp(this.value, 0, 100);
 
     // mute the effect if value is 0
-    if (this.value == 0) {
+    if (this.value === 0) {
         this.wet.value = 0;
     } else {
         this.wet.value = 0.5;
@@ -53,6 +53,7 @@ EchoEffect.prototype.changeBy = function (val) {
 * @param {number} input - the input to clamp
 * @param {number} min - the min value to clamp to
 * @param {number} max - the max value to clamp to
+* @return {number} the clamped value
 */
 EchoEffect.prototype.clamp = function (input, min, max) {
     return Math.min(Math.max(input, min), max);

src/effects/FuzzEffect.js

@@ -7,7 +7,7 @@ const Tone = require('tone');
 * Clamped 0-100
 * @constructor
 */
-function FuzzEffect () {
+const FuzzEffect = function () {
     Tone.Effect.call(this);
 
     this.value = 0;
@@ -15,7 +15,7 @@ function FuzzEffect () {
     this.distortion = new Tone.Distortion(1);
 
     this.effectSend.chain(this.distortion, this.effectReturn);
-}
+};
 
 Tone.extend(FuzzEffect, Tone.Effect);
 
@@ -43,6 +43,7 @@ FuzzEffect.prototype.changeBy = function (val) {
 * @param {number} input - the input to clamp
 * @param {number} min - the min value to clamp to
 * @param {number} max - the max value to clamp to
+* @return {number} the clamped value
 */
 FuzzEffect.prototype.clamp = function (input, min, max) {
     return Math.min(Math.max(input, min), max);

src/effects/PanEffect.js

@@ -7,7 +7,7 @@ const Tone = require('tone');
 * Clamped -100 to 100
 * @constructor
 */
-function PanEffect () {
+const PanEffect = function () {
     Tone.Effect.call(this);
 
     this.value = 0;
@@ -15,7 +15,7 @@ function PanEffect () {
     this.panner = new Tone.Panner();
 
     this.effectSend.chain(this.panner, this.effectReturn);
-}
+};
 
 Tone.extend(PanEffect, Tone.Effect);
 
@@ -44,6 +44,7 @@ PanEffect.prototype.changeBy = function (val) {
 * @param {number} input - the input to clamp
 * @param {number} min - the min value to clamp to
 * @param {number} max - the max value to clamp to
+* @return {number} the clamped value
 */
 PanEffect.prototype.clamp = function (input, min, max) {
     return Math.min(Math.max(input, min), max);

src/effects/PitchEffect.js

@@ -18,12 +18,12 @@ const Tone = require('tone');
 * on one SoundPlayer or a group of them.
 * @constructor
 */
-function PitchEffect () {
+const PitchEffect = function () {
     this.value = 0; // effect value
     this.ratio = 1; // the playback rate ratio
 
     this.tone = new Tone();
-}
+};
 
 /**
 * Set the effect value
@@ -39,7 +39,7 @@ PitchEffect.prototype.set = function (val, players) {
 /**
 * Change the effect value
 * @param {number} val - the value to change the effect by
-* @param {Object} players - a dictionary of SoundPlayer objects indexed by md5
+* @param {object} players - a dictionary of SoundPlayer objects indexed by md5
 */
 PitchEffect.prototype.changeBy = function (val, players) {
     this.set(this.value + val, players);
@@ -58,7 +58,7 @@ PitchEffect.prototype.getRatio = function (val) {
 
 /**
 * Update a sound player's playback rate using the current ratio for the effect
-* @param {Object} player - a SoundPlayer object
+* @param {object} player - a SoundPlayer object
 */
 PitchEffect.prototype.updatePlayer = function (player) {
     player.setPlaybackRate(this.ratio);

src/effects/ReverbEffect.js

@@ -7,7 +7,7 @@ const Tone = require('tone');
 * Clamped 0 to 100
 * @constructor
 */
-function ReverbEffect () {
+const ReverbEffect = function () {
     Tone.Effect.call(this);
 
     this.value = 0;
@@ -15,7 +15,7 @@ function ReverbEffect () {
     this.reverb = new Tone.Freeverb();
 
     this.effectSend.chain(this.reverb, this.effectReturn);
-}
+};
 
 Tone.extend(ReverbEffect, Tone.Effect);
 
@@ -44,6 +44,7 @@ ReverbEffect.prototype.changeBy = function (val) {
 * @param {number} input - the input to clamp
 * @param {number} min - the min value to clamp to
 * @param {number} max - the max value to clamp to
+* @return {number} the clamped value
 */
 ReverbEffect.prototype.clamp = function (input, min, max) {
     return Math.min(Math.max(input, min), max);

src/effects/RoboticEffect.js

@@ -11,7 +11,7 @@ const Tone = require('tone');
 * Exterminate.
 * @constructor
 */
-function RoboticEffect () {
+const RoboticEffect = function () {
     Tone.Effect.call(this);
 
     this.value = 0;
@@ -20,7 +20,7 @@ function RoboticEffect () {
     this.feedbackCombFilter = new Tone.FeedbackCombFilter(time, 0.9);
 
     this.effectSend.chain(this.feedbackCombFilter, this.effectReturn);
-}
+};
 
 Tone.extend(RoboticEffect, Tone.Effect);
 
@@ -32,7 +32,7 @@ RoboticEffect.prototype.set = function (val) {
     this.value = val;
 
     // mute the effect if value is 0
-    if (this.value == 0) {
+    if (this.value === 0) {
         this.wet.value = 0;
     } else {
         this.wet.value = 1;

src/effects/WobbleEffect.js

@@ -11,7 +11,7 @@ const Tone = require('tone');
 * Clamped 0 to 100
 * @constructor
 */
-function WobbleEffect () {
+const WobbleEffect = function () {
     Tone.Effect.call(this);
 
     this.value = 0;
@@ -21,7 +21,7 @@ function WobbleEffect () {
     this.wobbleLFO.connect(this.wobbleGain.gain);
 
     this.effectSend.chain(this.wobbleGain, this.effectReturn);
-}
+};
 
 Tone.extend(WobbleEffect, Tone.Effect);
 
@@ -52,6 +52,7 @@ WobbleEffect.prototype.changeBy = function (val) {
 * @param {number} input - the input to clamp
 * @param {number} min - the min value to clamp to
 * @param {number} max - the max value to clamp to
+* @return {number} the clamped value
 */
 WobbleEffect.prototype.clamp = function (input, min, max) {
     return Math.min(Math.max(input, min), max);

src/index.js

@@ -19,195 +19,14 @@ const DrumPlayer = require('./DrumPlayer');
  * that handles global functionality, and AudioPlayers, belonging to individual sprites and clones.
  */
 
-/**
- * There is a single instance of the AudioEngine. It handles global audio properties and effects,
- * loads all the audio buffers for sounds belonging to sprites, and creates a single instrument player
- * and a drum player, used by all play note and play drum blocks.
- * @constructor
- */
-function AudioEngine () {
-
-    // create the global audio effects
-    this.roboticEffect = new RoboticEffect();
-    this.fuzzEffect = new FuzzEffect();
-    this.echoEffect = new EchoEffect();
-    this.reverbEffect = new ReverbEffect();
-
-    // chain the global effects to the output
-    this.input = new Tone.Gain();
-    this.input.chain(
-        this.roboticEffect, this.fuzzEffect, this.echoEffect, this.reverbEffect,
-        Tone.Master
-    );
-
-    // global tempo in bpm (beats per minute)
-    this.currentTempo = 60;
-
-    // instrument player for play note blocks
-    this.instrumentPlayer = new InstrumentPlayer(this.input);
-    this.numInstruments = this.instrumentPlayer.instrumentNames.length;
-
-    // drum player for play drum blocks
-    this.drumPlayer = new DrumPlayer(this.input);
-    this.numDrums = this.drumPlayer.drumSounds.length;
-
-    // a map of md5s to audio buffers, holding sounds for all sprites
-    this.audioBuffers = {};
-
-    // microphone, for measuring loudness, with a level meter analyzer
-    this.mic = null;
-    this.micMeter = null;
-}
-
-/**
- * Decode a sound, decompressing it into audio samples.
- * Store a reference to it the sound in the audioBuffers dictionary, indexed by md5
- * @param  {Object} sound - an object containing audio data and metadata for a sound
- * @property {Buffer} data - sound data loaded from scratch-storage.
- * @property {string} format - format type, either empty or adpcm.
- * @property {string} md5 - the MD5 and extension of the sound.
- * @returns {?Promise} - a promise which will resolve after the audio buffer is stored, or null on error.
- */
-AudioEngine.prototype.decodeSound = function (sound) {
-
-    let loaderPromise = null;
-
-    switch (sound.format) {
-    case '':
-        loaderPromise = Tone.context.decodeAudioData(sound.data.buffer);
-        break;
-    case 'adpcm':
-        loaderPromise = (new ADPCMSoundDecoder()).decode(sound.data.buffer);
-        break;
-    default:
-        return log.warn('unknown sound format', sound.format);
-    }
-
-    const storedContext = this;
-    return loaderPromise.then(
-        decodedAudio => {
-            storedContext.audioBuffers[sound.md5] = new Tone.Buffer(decodedAudio);
-        },
-        error => {
-            log.warn('audio data could not be decoded', error);
-        }
-    );
-};
-
-/**
- * An older version of the AudioEngine had this function to load all sounds
- * This is a stub to provide a warning when it is called
- * @todo remove this
- */
-AudioEngine.prototype.loadSounds = function () {
-    log.warn('The loadSounds function is no longer available. Please use Scratch Storage.');
-};
-
-/**
- * Play a note for a duration on an instrument with a volume
- * @param  {number} note - a MIDI note number
- * @param  {number} beats - a duration in beats
- * @param  {number} inst - an instrument number (0-indexed)
- * @param  {number} vol - a volume level (0-100%)
- * @return {Promise} a Promise that resolves after the duration has elapsed
- */
-AudioEngine.prototype.playNoteForBeatsWithInstAndVol = function (note, beats, inst, vol) {
-    const sec = this.beatsToSec(beats);
-    this.instrumentPlayer.playNoteForSecWithInstAndVol(note, sec, inst, vol);
-    return this.waitForBeats(beats);
-};
-
-/**
- * Convert a number of beats to a number of seconds, using the current tempo
- * @param  {number} beats
- * @return {number} seconds
- */
-AudioEngine.prototype.beatsToSec = function (beats) {
-    return (60 / this.currentTempo) * beats;
-};
-
-/**
- * Wait for some number of beats
- * @param  {number} beats
- * @return {Promise} a Promise that resolves after the duration has elapsed
- */
-AudioEngine.prototype.waitForBeats = function (beats) {
-    const storedContext = this;
-    return new Promise(resolve => {
-        setTimeout(() => {
-            resolve();
-        }, storedContext.beatsToSec(beats) * 1000);
-    });
-};
-
-/**
- * Set the global tempo in bpm (beats per minute)
- * @param {number} value - the new tempo to set
- */
-AudioEngine.prototype.setTempo = function (value) {
-    this.currentTempo = value;
-};
-
-/**
- * Change the tempo by some number of bpm (beats per minute)
- * @param  {number} value - the number of bpm to change the tempo by
- */
-AudioEngine.prototype.changeTempo = function (value) {
-    this.setTempo(this.currentTempo + value);
-};
-
-/**
- * Get the current loudness of sound received by the microphone.
- * Sound is measured in RMS and smoothed.
- * @return {number} loudness scaled 0 to 100
- */
-AudioEngine.prototype.getLoudness = function () {
-    if (!this.mic) {
-        this.mic = new Tone.UserMedia();
-        this.micMeter = new Tone.Meter('level', 0.5);
-        this.mic.open();
-        this.mic.connect(this.micMeter);
-    }
-    if (this.mic && this.mic.state == 'started') {
-        return this.micMeter.value * 100;
-    }
-    return -1;
-    
-};
-
-/**
- * Names of the audio effects.
- * @readonly
- * @enum {string}
- */
-AudioEngine.prototype.EFFECT_NAMES = {
-    pitch: 'pitch',
-    pan: 'pan',
-    echo: 'echo',
-    reverb: 'reverb',
-    fuzz: 'fuzz',
-    robot: 'robot'
-};
-
-/**
- * Create an AudioPlayer. Each sprite or clone has an AudioPlayer.
- * It includes a reference to the AudioEngine so it can use global
- * functionality such as playing notes.
- * @return {AudioPlayer}
- */
-AudioEngine.prototype.createPlayer = function () {
-    return new AudioPlayer(this);
-};
-
-
 /**
  * Each sprite or clone has an audio player
  * the audio player handles sound playback, volume, and the sprite-specific audio effects:
  * pitch and pan
- * @param {AudioEngine}
+ * @param {AudioEngine} audioEngine AudioEngine for player
  * @constructor
  */
-function AudioPlayer (audioEngine) {
+const AudioPlayer = function (audioEngine) {
 
     this.audioEngine = audioEngine;
 
@@ -226,7 +45,7 @@ function AudioPlayer (audioEngine) {
 
     // sound players that are currently playing, indexed by the sound's md5
     this.activeSoundPlayers = {};
-}
+};
 
 /**
  * Play a sound
@@ -344,4 +163,185 @@ AudioPlayer.prototype.setVolume = function (value) {
     this.effectsNode.gain.value = value / 100;
 };
 
+
+/**
+ * There is a single instance of the AudioEngine. It handles global audio properties and effects,
+ * loads all the audio buffers for sounds belonging to sprites, and creates a single instrument player
+ * and a drum player, used by all play note and play drum blocks.
+ * @constructor
+ */
+const AudioEngine = function () {
+
+    // create the global audio effects
+    this.roboticEffect = new RoboticEffect();
+    this.fuzzEffect = new FuzzEffect();
+    this.echoEffect = new EchoEffect();
+    this.reverbEffect = new ReverbEffect();
+
+    // chain the global effects to the output
+    this.input = new Tone.Gain();
+    this.input.chain(
+        this.roboticEffect, this.fuzzEffect, this.echoEffect, this.reverbEffect,
+        Tone.Master
+    );
+
+    // global tempo in bpm (beats per minute)
+    this.currentTempo = 60;
+
+    // instrument player for play note blocks
+    this.instrumentPlayer = new InstrumentPlayer(this.input);
+    this.numInstruments = this.instrumentPlayer.instrumentNames.length;
+
+    // drum player for play drum blocks
+    this.drumPlayer = new DrumPlayer(this.input);
+    this.numDrums = this.drumPlayer.drumSounds.length;
+
+    // a map of md5s to audio buffers, holding sounds for all sprites
+    this.audioBuffers = {};
+
+    // microphone, for measuring loudness, with a level meter analyzer
+    this.mic = null;
+    this.micMeter = null;
+};
+
+/**
+ * Decode a sound, decompressing it into audio samples.
+ * Store a reference to it the sound in the audioBuffers dictionary, indexed by md5
+ * @param  {object} sound - an object containing audio data and metadata for a sound
+ * @property {Buffer} data - sound data loaded from scratch-storage.
+ * @property {string} format - format type, either empty or adpcm.
+ * @property {string} md5 - the MD5 and extension of the sound.
+ * @returns {?Promise} - a promise which will resolve after the audio buffer is stored, or null on error.
+ */
+AudioEngine.prototype.decodeSound = function (sound) {
+
+    let loaderPromise = null;
+
+    switch (sound.format) {
+    case '':
+        loaderPromise = Tone.context.decodeAudioData(sound.data.buffer);
+        break;
+    case 'adpcm':
+        loaderPromise = (new ADPCMSoundDecoder()).decode(sound.data.buffer);
+        break;
+    default:
+        return log.warn('unknown sound format', sound.format);
+    }
+
+    const storedContext = this;
+    return loaderPromise.then(
+        decodedAudio => {
+            storedContext.audioBuffers[sound.md5] = new Tone.Buffer(decodedAudio);
+        },
+        error => {
+            log.warn('audio data could not be decoded', error);
+        }
+    );
+};
+
+/**
+ * An older version of the AudioEngine had this function to load all sounds
+ * This is a stub to provide a warning when it is called
+ * @todo remove this
+ */
+AudioEngine.prototype.loadSounds = function () {
+    log.warn('The loadSounds function is no longer available. Please use Scratch Storage.');
+};
+
+/**
+ * Play a note for a duration on an instrument with a volume
+ * @param  {number} note - a MIDI note number
+ * @param  {number} beats - a duration in beats
+ * @param  {number} inst - an instrument number (0-indexed)
+ * @param  {number} vol - a volume level (0-100%)
+ * @return {Promise} a Promise that resolves after the duration has elapsed
+ */
+AudioEngine.prototype.playNoteForBeatsWithInstAndVol = function (note, beats, inst, vol) {
+    const sec = this.beatsToSec(beats);
+    this.instrumentPlayer.playNoteForSecWithInstAndVol(note, sec, inst, vol);
+    return this.waitForBeats(beats);
+};
+
+/**
+ * Convert a number of beats to a number of seconds, using the current tempo
+ * @param  {number} beats number of beats to convert to secs
+ * @return {number} seconds number of seconds `beats` will last
+ */
+AudioEngine.prototype.beatsToSec = function (beats) {
+    return (60 / this.currentTempo) * beats;
+};
+
+/**
+ * Wait for some number of beats
+ * @param  {number} beats number of beats to wait for
+ * @return {Promise} a Promise that resolves after the duration has elapsed
+ */
+AudioEngine.prototype.waitForBeats = function (beats) {
+    const storedContext = this;
+    return new Promise(resolve => {
+        setTimeout(() => {
+            resolve();
+        }, storedContext.beatsToSec(beats) * 1000);
+    });
+};
+
+/**
+ * Set the global tempo in bpm (beats per minute)
+ * @param {number} value - the new tempo to set
+ */
+AudioEngine.prototype.setTempo = function (value) {
+    this.currentTempo = value;
+};
+
+/**
+ * Change the tempo by some number of bpm (beats per minute)
+ * @param  {number} value - the number of bpm to change the tempo by
+ */
+AudioEngine.prototype.changeTempo = function (value) {
+    this.setTempo(this.currentTempo + value);
+};
+
+/**
+ * Get the current loudness of sound received by the microphone.
+ * Sound is measured in RMS and smoothed.
+ * @return {number} loudness scaled 0 to 100
+ */
+AudioEngine.prototype.getLoudness = function () {
+    if (!this.mic) {
+        this.mic = new Tone.UserMedia();
+        this.micMeter = new Tone.Meter('level', 0.5);
+        this.mic.open();
+        this.mic.connect(this.micMeter);
+    }
+    if (this.mic && this.mic.state === 'started') {
+        return this.micMeter.value * 100;
+    }
+    return -1;
+
+};
+
+/**
+ * Names of the audio effects.
+ * @readonly
+ * @enum {string}
+ */
+AudioEngine.prototype.EFFECT_NAMES = {
+    pitch: 'pitch',
+    pan: 'pan',
+    echo: 'echo',
+    reverb: 'reverb',
+    fuzz: 'fuzz',
+    robot: 'robot'
+};
+
+/**
+ * Create an AudioPlayer. Each sprite or clone has an AudioPlayer.
+ * It includes a reference to the AudioEngine so it can use global
+ * functionality such as playing notes.
+ * @return {AudioPlayer} new AudioPlayer instance
+ */
+AudioEngine.prototype.createPlayer = function () {
+    return new AudioPlayer(this);
+};
+
 module.exports = AudioEngine;