Backport PR #6951

---------

**Commit 1:**
[internal] Replace var with let in ui/public/utils (no rison)

This change was applied to any .js files under the src/ui/public/utils
directory except for the `rison.js` file. The rison code has block level
hoisting issues, but it seems safer to just not touch the file rather
than fix them.

This was an automatic replacement from var to let for any variable
declaration that doubles as the initial assignment. Ultimately we want
most of these to be converted to const, but this commit is so large that
it warrants breaking each step of automation up into its own commit.

For example:

`var foo = 'bar';` becomes `let foo = 'var';`

This was accomplished by replacing:
find: `var ([a-zA-Z_$][0-9a-zA-Z_$]*)(\s+)=`
replace: `let $1$2=`

* Original sha: ec0707f
* Authored by Court Ewing <[email protected]> on 2016-04-15T21:20:57Z

Author: elastic-jasper

src/ui/public/utils/BaseObject.js

@@ -1,7 +1,7 @@
 define(function (require) {
-  var _ = require('lodash');
-  var rison = require('ui/utils/rison');
-  var angular = require('angular');
+  let _ = require('lodash');
+  let rison = require('ui/utils/rison');
+  let angular = require('angular');
 
   function BaseObject(attributes) {
     // Set the attributes or default to an empty object

src/ui/public/utils/CidrMask.js

@@ -1,23 +1,23 @@
 define(function (require) {
-  var Ipv4Address = require('ui/utils/Ipv4Address');
-  var NUM_BITS = 32;
+  let Ipv4Address = require('ui/utils/Ipv4Address');
+  let NUM_BITS = 32;
 
   function throwError(mask) {
     throw Error('Invalid CIDR mask: ' + mask);
   }
 
   function CidrMask(mask) {
-    var splits = mask.split('\/');
+    let splits = mask.split('\/');
     if (splits.length !== 2) throwError(mask);
     this.initialAddress = new Ipv4Address(splits[0]);
     this.prefixLength = Number(splits[1]);
     if (this.prefixLength < 1 || this.prefixLength > NUM_BITS) throwError(mask);
   }
 
   CidrMask.prototype.getRange = function () {
-    var variableBits = NUM_BITS - this.prefixLength;
-    var fromAddress = this.initialAddress.valueOf() >> variableBits << variableBits >>> 0; // >>> 0 coerces to unsigned
-    var numAddresses = Math.pow(2, variableBits);
+    let variableBits = NUM_BITS - this.prefixLength;
+    let fromAddress = this.initialAddress.valueOf() >> variableBits << variableBits >>> 0; // >>> 0 coerces to unsigned
+    let numAddresses = Math.pow(2, variableBits);
     return {
       from: new Ipv4Address(fromAddress).toString(),
       to: new Ipv4Address(fromAddress + numAddresses - 1).toString()

src/ui/public/utils/Ipv4Address.js

@@ -1,6 +1,6 @@
 define(function () {
-  var NUM_BYTES = 4;
-  var BYTE_SIZE = 256;
+  let NUM_BYTES = 4;
+  let BYTE_SIZE = 256;
 
   function throwError(ipAddress) {
     throw Error('Invalid IPv4 address: ' + ipAddress);
@@ -19,11 +19,11 @@ define(function () {
     if (typeof ipAddress === 'string') {
       this.value = 0;
 
-      var bytes = ipAddress.split('.');
+      let bytes = ipAddress.split('.');
       if (bytes.length !== NUM_BYTES) throwError(ipAddress);
 
-      for (var i = 0; i < bytes.length; i++) {
-        var byte = Number(bytes[i]);
+      for (let i = 0; i < bytes.length; i++) {
+        let byte = Number(bytes[i]);
         if (!isIntegerInRange(byte, 0, BYTE_SIZE)) throwError(ipAddress);
         this.value += Math.pow(BYTE_SIZE, NUM_BYTES - 1 - i) * byte;
       }
@@ -33,9 +33,9 @@ define(function () {
   }
 
   Ipv4Address.prototype.toString = function () {
-    var value = this.value;
-    var bytes = [];
-    for (var i = 0; i < NUM_BYTES; i++) {
+    let value = this.value;
+    let bytes = [];
+    for (let i = 0; i < NUM_BYTES; i++) {
       bytes.unshift(value % 256);
       value = Math.floor(value / 256);
     }

src/ui/public/utils/ObjDefine.js

@@ -1,5 +1,5 @@
 define(function (require) {
-  var _ = require('lodash');
+  let _ = require('lodash');
 
   function ObjDefine(defaults, prototype) {
     this.obj; // created by this.create()
@@ -10,7 +10,7 @@ define(function (require) {
   }
 
   ObjDefine.REDEFINE_SUPPORTED = (function () {
-    var a = Object.create(Object.prototype, {
+    let a = Object.create(Object.prototype, {
       prop: {
         configurable: true,
         value: 1
@@ -67,7 +67,7 @@ define(function (require) {
    * @return {object} - created object
    */
   ObjDefine.prototype.create = function () {
-    var self = this;
+    let self = this;
     self.obj = Object.create(this.prototype, self.descs);
 
     if (!ObjDefine.REDEFINE_SUPPORTED && !self.prototype.toJSON) {
@@ -77,7 +77,7 @@ define(function (require) {
       // due to https://github.com/ariya/phantomjs/issues/11856
       self.obj.toJSON = function () {
         return _.transform(self.obj, function (json, val, key) {
-          var desc = self.descs[key];
+          let desc = self.descs[key];
           if (desc && desc.enumerable && val == null) return;
           json[key] = val;
         }, {});
@@ -98,8 +98,8 @@ define(function (require) {
   };
 
   ObjDefine.prototype._describe = function (name, val, exported, changeable) {
-    var self = this;
-    var exists = val != null;
+    let self = this;
+    let exists = val != null;
 
     if (exported && ObjDefine.REDEFINE_SUPPORTED) {
       return {

src/ui/public/utils/SimpleEmitter.js

@@ -1,6 +1,6 @@
 define(function (require) {
-  var _ = require('lodash');
-  var BaseObject = require('ui/utils/BaseObject');
+  let _ = require('lodash');
+  let BaseObject = require('ui/utils/BaseObject');
 
   /**
    * Simple event emitter class used in the vislib. Calls
@@ -21,7 +21,7 @@ define(function (require) {
    * @return {SimpleEmitter} - this, for chaining
    */
   SimpleEmitter.prototype.on = function (name, handler) {
-    var handlers = this._listeners[name];
+    let handlers = this._listeners[name];
     if (!handlers) handlers = this._listeners[name] = [];
 
     handlers.push(handler);
@@ -69,8 +69,8 @@ define(function (require) {
    */
   SimpleEmitter.prototype.emit = _.restParam(function (name, args) {
     if (!this._listeners[name]) return this;
-    var listeners = this.listeners(name);
-    var i = -1;
+    let listeners = this.listeners(name);
+    let i = -1;
 
     while (++i < listeners.length) {
       listeners[i].apply(this, args);

src/ui/public/utils/add_word_breaks.js

@@ -1,13 +1,13 @@
 define(function () {
   return function addWordBreaks(text, minLineLength) {
     text = text || '';
-    var lineSize = 0;
-    var newText = '';
-    var inHtmlTag = false;
-    var inHtmlChar = false;
+    let lineSize = 0;
+    let newText = '';
+    let inHtmlTag = false;
+    let inHtmlChar = false;
 
-    for (var i = 0, len = text.length; i < len; i++) {
-      var chr = text.charAt(i);
+    for (let i = 0, len = text.length; i < len; i++) {
+      let chr = text.charAt(i);
       newText += chr;
 
       switch (chr) {

src/ui/public/utils/brush_event.js

@@ -1,9 +1,9 @@
 define(function (require) {
-  var moment = require('moment');
+  let moment = require('moment');
   return function brushEventProvider(timefilter) {
     return function (event) {
-      var from = moment(event.range[0]);
-      var to = moment(event.range[1]);
+      let from = moment(event.range[0]);
+      let to = moment(event.range[1]);
 
       if (to - from === 0) return;
 

src/ui/public/utils/dateMath.js

@@ -1,12 +1,12 @@
 define(function (require) {
-  var _ = require('lodash');
-  var moment = require('moment');
+  let _ = require('lodash');
+  let moment = require('moment');
 
-  var units = ['y', 'M', 'w', 'd', 'h', 'm', 's'];
-  var unitsAsc = _.sortBy(units, function (unit) {
+  let units = ['y', 'M', 'w', 'd', 'h', 'm', 's'];
+  let unitsAsc = _.sortBy(units, function (unit) {
     return moment.duration(1, unit).valueOf();
   });
-  var unitsDesc = unitsAsc.reverse();
+  let unitsDesc = unitsAsc.reverse();
 
   /* This is a simplified version of elasticsearch's date parser */
   function parse(text, roundUp) {
@@ -15,7 +15,7 @@ define(function (require) {
     if (_.isDate(text)) return moment(text);
 
     let time;
-    var mathString = '';
+    let mathString = '';
     let index;
     let parseString;
 
@@ -43,12 +43,12 @@ define(function (require) {
   }
 
   function parseDateMath(mathString, time, roundUp) {
-    var dateTime = time;
-    var i = 0;
-    var len = mathString.length;
+    let dateTime = time;
+    let i = 0;
+    let len = mathString.length;
 
     while (i < len) {
-      var c = mathString.charAt(i++);
+      let c = mathString.charAt(i++);
       let type;
       let num;
       let unit;
@@ -68,7 +68,7 @@ define(function (require) {
       } else if (mathString.length === 2) {
         num = mathString.charAt(i);
       } else {
-        var numFrom = i;
+        let numFrom = i;
         while (!isNaN(mathString.charAt(i))) {
           i++;
           if (i > 10) return undefined;

src/ui/public/utils/date_range.js

@@ -1,5 +1,5 @@
 define(function (require) {
-  var moment = require('moment');
+  let moment = require('moment');
 
   return {
     toString: function (range, format) {
@@ -12,7 +12,7 @@ define(function (require) {
       }
     },
     parse: function (rangeString, format) {
-      var chunks = rangeString.split(' to ');
+      let chunks = rangeString.split(' to ');
       if (chunks.length === 2) return {from: moment(chunks[0], format), to: moment(chunks[1], format)};
 
       chunks = rangeString.split('Before ');

src/ui/public/utils/decode_geo_hash.js

@@ -17,22 +17,22 @@ define(function (require) {
    * @return {Object} interval
    */
   function decodeGeoHash(geohash) {
-    var BITS = [16, 8, 4, 2, 1];
-    var BASE32 = '0123456789bcdefghjkmnpqrstuvwxyz';
-    var is_even = 1;
-    var lat = [];
-    var lon = [];
+    let BITS = [16, 8, 4, 2, 1];
+    let BASE32 = '0123456789bcdefghjkmnpqrstuvwxyz';
+    let is_even = 1;
+    let lat = [];
+    let lon = [];
     lat[0] = -90.0;
     lat[1] = 90.0;
     lon[0] = -180.0;
     lon[1] = 180.0;
-    var lat_err = 90.0;
-    var lon_err = 180.0;
-    for (var i = 0; i < geohash.length; i++) {
-      var c = geohash[i];
-      var cd = BASE32.indexOf(c);
-      for (var j = 0; j < 5; j++) {
-        var mask = BITS[j];
+    let lat_err = 90.0;
+    let lon_err = 180.0;
+    for (let i = 0; i < geohash.length; i++) {
+      let c = geohash[i];
+      let cd = BASE32.indexOf(c);
+      for (let j = 0; j < 5; j++) {
+        let mask = BITS[j];
         if (is_even) {
           lon_err /= 2;
           refine_interval(lon, cd, mask);