docs: replace var in with let/const

docs/_guides/attachments.md

@@ -116,8 +116,8 @@ db.put({
 }).then(function () {
   return db.getAttachment('meowth', 'meowth.png');
 }).then(function (blob) {
-  var url = URL.createObjectURL(blob);
-  var img = document.createElement('img');
+  const url = URL.createObjectURL(blob);
+  const img = document.createElement('img');
   img.src = url;
   document.body.appendChild(img);
 }).catch(function (err) {
@@ -150,16 +150,16 @@ For instance, we can read the image data from an `<img>` tag using a `canvas` el
 
 ```js
 function convertImgToBlob(img, callback) {
-   var canvas = document.createElement('canvas');
-   var context = canvas.getContext('2d');
+   const canvas = document.createElement('canvas');
+   const context = canvas.getContext('2d');
    context.drawImage(img, 0, 0);
 
     // Warning: toBlob() isn't supported by every browser.
     // You may want to use blob-util.
    canvas.toBlob(callback, 'image/png');
 }
 
-var catImage = document.getElementById('cat');
+const catImage = document.getElementById('cat');
 convertImgToBlob(catImage, function (blob) {
   db.putAttachment('meowth', 'meowth.png', blob, 'image/png').then(function () {
     return db.get('meowth', {attachments: true});
@@ -196,9 +196,9 @@ Here is an example of allowing a user to choose a file from their filesystem:
 And then "uploading" that file directly into PouchDB:
 
 ```js
-var input = document.querySelector('input');
+const input = document.querySelector('input');
 input.addEventListener('change', function () {
-  var file = input.files[0]; // file is a Blob
+  const file = input.files[0]; // file is a Blob
 
   db.put({
     _id: 'mydoc',
@@ -285,7 +285,7 @@ The other "read" APIs, such as `get()`, `allDocs()`, `changes()`, and `query()`
 Blobs have their own `type`, but there is also a `content_type` that you specify when you store it in PouchDB:
 
 ```js
-var myBlob = new Blob(['I am plain text!'], {type: 'text/plain'});
+const myBlob = new Blob(['I am plain text!'], {type: 'text/plain'});
 console.log(myBlob.type); // 'text/plain'
 
 db.put({

docs/_guides/changes.md

@@ -43,8 +43,8 @@ Also notice the option `{include_docs: true}`. By default, the documents themsel
 If you expect this to be a very large number of changes, you can also use the `limit` option to do pagination:
 
 ```js
-var pageSize = 10;
-var lastSeq = 0;
+const pageSize = 10;
+let lastSeq = 0;
 function fetchNextPage() {
   return db.changes({
     since: lastSeq,

docs/_guides/compact-and-destroy.md

@@ -52,7 +52,7 @@ However, if that's not a concern, then compaction is a harmless operation. In fa
 If you really want to go all-in on compaction, then you can even put your database in `auto_compaction` mode. This means that it will automatically perform a `compact()` operation after every write.
 
 ```js
-var db = new PouchDB('mydb', {auto_compaction: true});
+const db = new PouchDB('mydb', {auto_compaction: true});
 db.put({_id: 'foo', version: 1}).then(function () {
   return db.get('foo');
 }).then(function (doc) {

docs/_guides/conflicts.md

@@ -24,7 +24,7 @@ In CouchDB, conflicts can occur in two places: immediately, when you try to comm
 **Immediate conflicts** can occur with any API that takes a `rev` or a document with `_rev` as input – `put()`, `post()`, `remove()`, `bulkDocs()`, and `putAttachment()`. They manifest as a `409` (conflict) error:
 
 ```js
-var myDoc = {
+const myDoc = {
   _id: 'someid',
   _rev: '1-somerev'
 };

docs/_guides/databases.md

@@ -12,7 +12,7 @@ PouchDB databases come in two flavors: local and remote.
 To create a local database, you simply call `new PouchDB` and give it a name:
 
 ```js
-var db = new PouchDB('kittens');
+const db = new PouchDB('kittens');
 ```
 
 You can see a **[live example](http://bl.ocks.org/nolanlawson/bddac54b92c2d8d39241)** of this code.
@@ -37,7 +37,7 @@ Now the site is up and running at <a href='http://localhost:8000'>http://localho
 To create a remote database, you call `new PouchDB` and give it a path to a database in CouchDB.
 
 ```js
-var db = new PouchDB('http://localhost:5984/kittens');
+const db = new PouchDB('http://localhost:5984/kittens');
 ```
 
 {% include alert/start.html variant="info" %}

docs/_guides/documents.md

@@ -64,7 +64,7 @@ We'll discuss these concepts later on.
 To store a document, you simply `put` it:
 
 ```js
-var doc = {
+const doc = {
   "_id": "mittens",
   "name": "Mittens",
   "occupation": "kitten",

docs/_guides/mango-queries.md

@@ -36,7 +36,7 @@ If you are using Node, Browserify, Webpack, Rollup, etc., then you can install i
 Then in code:
 
 ```js
-var PouchDB = require('pouchdb');
+const PouchDB = require('pouchdb');
 PouchDB.plugin(require('pouchdb-find'));
 ```
 

docs/_guides/queries.md

@@ -50,7 +50,7 @@ First, you create a **design document**, which describes the `map` function you
 ```js
 // document that tells PouchDB/CouchDB
 // to build up an index on doc.name
-var ddoc = {
+const ddoc = {
   _id: '_design/my_index',
   views: {
     by_name: {
@@ -203,7 +203,7 @@ As for _reduce_ functions, there are a few handy built-ins that do aggregate ope
 
 ```js
 // emit the first letter of each pokemon's name
-var myMapReduceFun = {
+const myMapReduceFun = {
   map: function (doc) {
     emit(doc.name.charAt(0));
   },

docs/_guides/replication.md

@@ -42,13 +42,13 @@ In this way, CouchDB replication "just works."
 As you already know, you can create either local PouchDBs:
 
 ```js
-var localDB = new PouchDB('mylocaldb')
+const localDB = new PouchDB('mylocaldb')
 ```
 
 or remote PouchDBs:
 
 ```js
-var remoteDB = new PouchDB('http://localhost:5984/myremotedb')
+const remoteDB = new PouchDB('http://localhost:5984/myremotedb')
 ```
 
 This pattern comes in handy when you want to share data between the two.
@@ -132,7 +132,7 @@ This is ideal for scenarios where the user may be flitting in and out of connect
 Sometimes, you may want to manually cancel replication – for instance, because the user logged out. You can do so by calling `cancel()` and then waiting for the `'complete'` event:
 
 ```js
-var syncHandler = localDB.sync(remoteDB, {
+const syncHandler = localDB.sync(remoteDB, {
   live: true,
   retry: true
 });
@@ -147,7 +147,7 @@ syncHandler.cancel(); // <-- this cancels it
 The `replicate` API also supports canceling:
 
 ```js
-var replicationHandler = localDB.replicate.to(remoteDB, {
+const replicationHandler = localDB.replicate.to(remoteDB, {
   live: true,
   retry: true
 });

docs/_guides/setup-pouchdb.md

@@ -63,7 +63,7 @@ $ npm install pouchdb
 Then in your JavaScript:
 
 ```js
-var PouchDB = require('pouchdb');
+const PouchDB = require('pouchdb');
 ```
 
 {% include anchor.html title="With TypeScript" hash="typescript" %}

docs/_includes/api/active_tasks.html

@@ -9,7 +9,7 @@
 #### Example Usage:
 
 {% highlight js %}
-var tasks = PouchDB.activeTasks.list()
+const tasks = PouchDB.activeTasks.list()
 {% endhighlight %}
 
 #### Example Result:

docs/_includes/api/batch_create.html

@@ -27,7 +27,7 @@
 {% include code/start.html id="bulk_docs_1" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.bulkDocs([
+  const result = await db.bulkDocs([
     {title : 'Lisa Says', _id: 'doc1'},
     {title : 'Space Oddity', _id: 'doc2'}
   ]);
@@ -67,7 +67,7 @@
 {% include code/start.html id="bulk_docs_2" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.bulkDocs([
+  const result = await db.bulkDocs([
     {title : 'Lisa Says'},
     {title : 'Space Oddity'}
   ]);
@@ -155,7 +155,7 @@
 {% include code/start.html id="bulk_docs3" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.bulkDocs([
+  const result = await db.bulkDocs([
     {
       title  : 'Lisa Says',
       artist : 'Velvet Underground',
@@ -225,7 +225,7 @@
 {% include code/start.html id="bulk_docs_4" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.bulkDocs([
+  const result = await db.bulkDocs([
     {
       title    : 'Lisa Says',
       _deleted : true,

docs/_includes/api/batch_fetch.html

@@ -47,7 +47,7 @@
 {% include code/start.html id="all_docs" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.allDocs({
+  const result = await db.allDocs({
     include_docs: true,
     attachments: true
   });
@@ -125,7 +125,7 @@
 {% include code/start.html id="all_docs_2" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.allDocs({
+  const result = await db.allDocs({
     include_docs: true,
     attachments: true,
     startkey: 'bar',
@@ -175,7 +175,7 @@
 {% include code/start.html id="all_docs_3" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.allDocs({
+  const result = await db.allDocs({
     include_docs: true,
     attachments: true,
     startkey: 'foo',

docs/_includes/api/bulk_get.html

@@ -38,7 +38,7 @@
 {% include code/start.html id="bulkget1" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.bulkGet({
+  const result = await db.bulkGet({
       docs: [
         { id: "doc-that-exists", rev: "1-967a00dff5e02add41819138abb3284d"},
         { id: "doc-that-does-not-exist", rev: "1-3a24009a9525bde9e4bfa8a99046b00d"},

docs/_includes/api/changes.html

@@ -42,7 +42,7 @@
 #### Example Usage:
 
 {% highlight js %}
-var changes = db.changes({
+const changes = db.changes({
   since: 'now',
   live: true,
   include_docs: true
@@ -161,7 +161,7 @@
 {% include code/start.html id="changes1" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.changes({
+  const result = await db.changes({
     limit: 10,
     since: 0
   });

docs/_includes/api/compaction.html

@@ -26,7 +26,7 @@
 {% include code/start.html id="compact" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.compact();
+  const result = await db.compact();
 } catch (err) {
   console.log(err);
 }

docs/_includes/api/create_database.html

@@ -39,21 +39,21 @@
 
 #### Example Usage:
 {% highlight js %}
-var db = new PouchDB('dbname');
+const db = new PouchDB('dbname');
 // or
-var db = new PouchDB('http://localhost:5984/dbname');
+const db = new PouchDB('http://localhost:5984/dbname');
 {% endhighlight %}
 
 Create an in-memory Pouch (must install `pouchdb-adapter-memory` first):
 
 {% highlight js %}
-var db = new PouchDB('dbname', {adapter: 'memory'});
+const db = new PouchDB('dbname', {adapter: 'memory'});
 {% endhighlight %}
 
 Create a remote PouchDB with special fetch options:
 
 {% highlight js %}
-var db = new PouchDB('http://example.com/dbname', {
+const db = new PouchDB('http://example.com/dbname', {
   fetch: function (url, opts) {
     opts.headers.set('X-Some-Special-Header', 'foo');
     return PouchDB.fetch(url, opts);

docs/_includes/api/create_document.html

@@ -30,7 +30,7 @@
 {% include code/start.html id="newDoc" type="async" %}
 {% highlight js %}
 try {
-  var response = await db.put({
+  const response = await db.put({
     _id: 'mydoc',
     title: 'Heroes'
   });
@@ -74,8 +74,8 @@
 {% include code/start.html id="updateDoc" type="async" %}
 {% highlight js %}
 try {
-  var doc = await db.get('mydoc');
-  var response = await db.put({
+  const doc = await db.get('mydoc');
+  const response = await db.put({
     _id: 'mydoc',
     _rev: doc._rev,
     title: "Let's Dance"
@@ -139,7 +139,7 @@
 {% include code/start.html id="post_doc" type="async" %}
 {% highlight js %}
 try {
-  var response = await db.post({
+  const response = await db.post({
     title: 'Ziggy Stardust'
   });
 } catch (err) {

docs/_includes/api/create_index.html

@@ -33,7 +33,7 @@
 {% include code/start.html id="create_idx" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.createIndex({
+  const result = await db.createIndex({
     index: {
       fields: ['foo']
     }
@@ -90,7 +90,7 @@
 {% include code/start.html id="create_idx2" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.createIndex({
+  const result = await db.createIndex({
     index: {
       fields: ['foo', 'bar', 'baz']
     }
@@ -133,7 +133,7 @@
 {% include code/start.html id="create_idx3" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.createIndex({
+  const result = await db.createIndex({
     index: {
       fields: ['person.address.zipcode']
     }
@@ -179,7 +179,7 @@
 {% include code/start.html id="create_idx4" type="async" %}
 {% highlight js %}
 try {
-  var result = await db.createIndex({
+  const result = await db.createIndex({
     index: {
       fields: ['foo', 'bar'],
       name: 'myindex',
@@ -242,7 +242,7 @@
 {% include code/start.html id="create_idx5" type="async" %}
 {% highlight js %}
 try {
-  var result = db.createIndex({
+  const result = db.createIndex({
     index: {
       fields: ['year', 'title'],
       partial_filter_selector: {
@@ -284,7 +284,7 @@
 When a PouchDB instance updates an index, it emits `indexing` events that include information about the progress of the index update task.
 
 {% highlight js %}
-var db = new PouchDB('my-docs');
+const db = new PouchDB('my-docs');
 
 db.on('indexing', function (event) {
   // called when indexes are updated