change Slider to ES6 class

src/ui/Slider.js

@@ -4,7 +4,8 @@ var EventManager = require('../lib/eventManager')
 var yo = require('yo-yo')
 var ui = require('../helpers/ui')
 
-function Slider (_traceManager) {
+class Slider {
+  constructor (_traceManager) {
     this.event = new EventManager()
     this.traceManager = _traceManager
     this.max
@@ -12,9 +13,9 @@ function Slider (_traceManager) {
     this.view
 
     this.previousValue = null
-}
+  }
 
-Slider.prototype.render = function () {
+  render () {
     var self = this
     var view = yo`<div>
         <input
@@ -32,25 +33,25 @@ Slider.prototype.render = function () {
       this.view = view
     }
     return view
-}
+  }
 
-Slider.prototype.init = function (length) {
+  init (length) {
     var slider = document.getElementById('slider')
     slider.setAttribute('max', length - 1)
     this.max = length - 1
     this.updateDisabled(length === 0)
     this.disabled = length === 0
     this.setValue(0)
-}
+  }
 
-Slider.prototype.onChange = function (event) {
+  onChange (event) {
     var value = parseInt(document.getElementById('slider').value)
     if (value === this.previousValue) return
     this.previousValue = value
     this.event.trigger('moved', [value])
-}
+  }
 
-Slider.prototype.setValue = function (value) {
+  setValue (value) {
     var slider = document.getElementById('slider')
     var diff = value - slider.value
     if (diff > 0) {
@@ -58,14 +59,23 @@ Slider.prototype.setValue = function (value) {
     } else {
       slider.stepDown(Math.abs(diff))
     }
-}
+  }
 
-Slider.prototype.updateDisabled = function (disabled) {
+  updateDisabled (disabled) {
     if (disabled) {
       document.getElementById('slider').setAttribute('disabled', true)
     } else {
       document.getElementById('slider').removeAttribute('disabled')
     }
+  }
+
+  show () {
+    this.view.style.display = 'block'
+  }
+
+  hide () {
+    this.view.style.display = 'none'
+  }
 }
 
 module.exports = Slider