这是indexloc提供的服务，不要输入任何密码
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mjwilson-googlemjwilson-google
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Merge pull request #270 from mjwilson-google/var
Use let instead of var in examples
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‎explainer.md

Lines changed: 25 additions & 25 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@ The following are some examples of common MIDI usage in JavaScript.
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This example shows how to request access to the MIDI system.
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```js
10-
var midi = null; // global MIDIAccess object
10+
let midi = null; // global MIDIAccess object
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1212
function onMIDISuccess( midiAccess ) {
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console.log( "MIDI ready!" );
@@ -26,7 +26,7 @@ This example shows how to request access to the MIDI system, including the
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ability to send and receive System Exclusive messages.
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```js
29-
var midi = null; // global MIDIAccess object
29+
let midi = null; // global MIDIAccess object
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function onMIDISuccess( midiAccess ) {
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console.log( "MIDI ready!" );
@@ -46,15 +46,15 @@ information to the console log, using ES6 for...of notation.
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```js
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function listInputsAndOutputs( midiAccess ) {
49-
for (var entry of midiAccess.inputs) {
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var input = entry[1];
49+
for (let entry of midiAccess.inputs) {
50+
let input = entry[1];
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console.log( "Input port [type:'" + input.type + "'] id:'" + input.id +
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"' manufacturer:'" + input.manufacturer + "' name:'" + input.name +
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"' version:'" + input.version + "'" );
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}
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56-
for (var entry of midiAccess.outputs) {
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var output = entry[1];
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for (let entry of midiAccess.outputs) {
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let output = entry[1];
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console.log( "Output port [type:'" + output.type + "'] id:'" + output.id +
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"' manufacturer:'" + output.manufacturer + "' name:'" + output.name +
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"' version:'" + output.version + "'" );
@@ -68,8 +68,8 @@ the console log.
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```js
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function onMIDIMessage( event ) {
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var str = "MIDI message received at timestamp " + event.timeStamp + "[" + event.data.length + " bytes]: ";
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for (var i=0; i<event.data.length; i++) {
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let str = "MIDI message received at timestamp " + event.timeStamp + "[" + event.data.length + " bytes]: ";
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for (let i=0; i<event.data.length; i++) {
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str += "0x" + event.data[i].toString(16) + " ";
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}
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console.log( str );
@@ -87,8 +87,8 @@ queues a corresponding note off message for 1 second later.
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```js
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function sendMiddleC( midiAccess, portID ) {
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var noteOnMessage = [0x90, 60, 0x7f]; // note on, middle C, full velocity
91-
var output = midiAccess.outputs.get(portID);
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let noteOnMessage = [0x90, 60, 0x7f]; // note on, middle C, full velocity
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let output = midiAccess.outputs.get(portID);
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output.send( noteOnMessage ); //omitting the timestamp means send immediately.
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output.send( [0x80, 60, 0x40], window.performance.now() + 1000.0 ); // Inlined array creation- note off, middle C,
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// release velocity = 64, timestamp = now + 1000ms.
@@ -100,8 +100,8 @@ This example loops all input messages on the first input port to the first
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output port - including System Exclusive messages.
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```js
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var midi = null; // global MIDIAccess object
104-
var output = null;
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let midi = null; // global MIDIAccess object
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let output = null;
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function echoMIDIMessage( event ) {
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if (output) {
@@ -111,7 +111,7 @@ function echoMIDIMessage( event ) {
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112112
function onMIDISuccess( midiAccess ) {
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console.log( "MIDI ready!" );
114-
var input = midiAccess.inputs.entries().next();
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let input = midiAccess.inputs.entries().next();
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if (input)
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input.onmidimessage = echoMIDIMessage;
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output = midiAccess.outputs.values().next().value;
@@ -135,14 +135,14 @@ are not. This sample is also hosted on <a href=
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"http://webaudiodemos.appspot.com/monosynth/index.html">webaudiodemos.appspot.com</a>.
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```js
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var context=null; // the Web Audio "context" object
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var midiAccess=null; // the MIDIAccess object.
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var oscillator=null; // the single oscillator
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var envelope=null; // the envelope for the single oscillator
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var attack=0.05; // attack speed
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var release=0.05; // release speed
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var portamento=0.05; // portamento/glide speed
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var activeNotes = []; // the stack of actively-pressed keys
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let context=null; // the Web Audio "context" object
139+
let midiAccess=null; // the MIDIAccess object.
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let oscillator=null; // the single oscillator
141+
let envelope=null; // the envelope for the single oscillator
142+
let attack=0.05; // attack speed
143+
let release=0.05; // release speed
144+
let portamento=0.05; // portamento/glide speed
145+
let activeNotes = []; // the stack of actively-pressed keys
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147147
window.addEventListener('load', function() {
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// patch up prefixes
@@ -167,9 +167,9 @@ window.addEventListener('load', function() {
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function onMIDIInit(midi) {
168168
midiAccess = midi;
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170-
var haveAtLeastOneDevice=false;
171-
var inputs=midiAccess.inputs.values();
172-
for ( var input = inputs.next(); input &amp;& !input.done; input = inputs.next()) {
170+
let haveAtLeastOneDevice=false;
171+
let inputs=midiAccess.inputs.values();
172+
for ( let input = inputs.next(); input &amp;& !input.done; input = inputs.next()) {
173173
input.value.onmidimessage = MIDIMessageEventHandler;
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haveAtLeastOneDevice = true;
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}
@@ -209,7 +209,7 @@ function noteOn(noteNumber) {
209209
}
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211211
function noteOff(noteNumber) {
212-
var position = activeNotes.indexOf(noteNumber);
212+
let position = activeNotes.indexOf(noteNumber);
213213
if (position!=-1) {
214214
activeNotes.splice(position,1);
215215
}

‎index.html

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -455,18 +455,18 @@ <h3 id="MIDIInputMap">
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ports. This enables:
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</p>
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<pre class="example"> // to tell how many entries there are:
458-
var numberOfMIDIInputs = inputs.size;
458+
let numberOfMIDIInputs = inputs.size;
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460460
// add each of the ports to a &lt;select&gt; box
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inputs.forEach( function( port, key ) {
462-
var opt = document.createElement("option");
462+
let opt = document.createElement("option");
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opt.text = port.name;
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document.getElementById("inputportselector").add(opt);
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});
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467467
// or you could express in ECMAScript 6 as:
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for (let input of inputs.values()) {
469-
var opt = document.createElement("option");
469+
let opt = document.createElement("option");
470470
opt.text = input.name;
471471
document.getElementById("inputportselector").add(opt);
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}</pre>
@@ -489,18 +489,18 @@ <h3 id="MIDIOutputMap">
489489
output ports=]. This enables:
490490
</p>
491491
<pre class="example"> // to tell how many entries there are:
492-
var numberOfMIDIOutputs = outputs.size;
492+
let numberOfMIDIOutputs = outputs.size;
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494494
// add each of the ports to a &lt;select&gt; box
495495
outputs.forEach( function( port, key ) {
496-
var opt = document.createElement("option");
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let opt = document.createElement("option");
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opt.text = port.name;
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document.getElementById("outputportselector").add(opt);
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});
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501501
// or you could express in ECMAScript 6 as:
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for (let output of outputs.values()) {
503-
var opt = document.createElement("option");
503+
let opt = document.createElement("option");
504504
opt.text = output.name;
505505
document.getElementById("outputportselector").add(opt);
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}</pre>

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