chore(deps): update eslint packages

.eslintrc.cjs

@@ -26,6 +26,7 @@ module.exports = {
   rules: {
     'import/newline-after-import': 'error',
     'max-statements-per-line': 'error',
+    'no-var': 'error',
     '@typescript-eslint/no-non-null-assertion': 'off',
     '@typescript-eslint/consistent-type-definitions': 'off',
     '@typescript-eslint/explicit-function-return-type': 'off',

README.md

@@ -69,16 +69,16 @@ import { styleModule } from 'snabbdom/modules/style'
 import { eventListenersModule } from 'snabbdom/modules/eventlisteners'
 import { h } from 'snabbdom/h' // helper function for creating vnodes
 
-var patch = init([ // Init patch function with chosen modules
+const patch = init([ // Init patch function with chosen modules
   classModule, // makes it easy to toggle classes
   propsModule, // for setting properties on DOM elements
   styleModule, // handles styling on elements with support for animations
   eventListenersModule, // attaches event listeners
 ])
 
-var container = document.getElementById('container')
+const container = document.getElementById('container')
 
-var vnode = h('div#container.two.classes', { on: { click: someFn } }, [
+const vnode = h('div#container.two.classes', { on: { click: someFn } }, [
   h('span', { style: { fontWeight: 'bold' } }, 'This is bold'),
   ' and this is just normal text',
   h('a', { props: { href: '/foo' } }, 'I\'ll take you places!')
@@ -86,7 +86,7 @@ var vnode = h('div#container.two.classes', { on: { click: someFn } }, [
 // Patch into empty DOM element – this modifies the DOM as a side effect
 patch(container, vnode)
 
-var newVnode = h('div#container.two.classes', { on: { click: anotherEventHandler } }, [
+const newVnode = h('div#container.two.classes', { on: { click: anotherEventHandler } }, [
   h('span', { style: { fontWeight: 'normal', fontStyle: 'italic' } }, 'This is now italic type'),
   ' and this is still just normal text',
   h('a', { props: { href: '/bar' } }, 'I\'ll take you places!')
@@ -160,7 +160,7 @@ specified set of modules.
 import { classModule } from 'snabbdom/modules/class'
 import { styleModule } from 'snabbdom/modules/style'
 
-var patch = init([classModule, styleModule])
+const patch = init([classModule, styleModule])
 ```
 
 ### `patch`
@@ -203,7 +203,7 @@ array of children.
 ```mjs
 import { h } from 'snabbdom/h'
 
-var vnode = h('div', { style: { color: '#000' } }, [
+const vnode = h('div', { style: { color: '#000' } }, [
   h('h1', 'Headline'),
   h('p', 'A paragraph'),
 ])
@@ -223,14 +223,14 @@ import { eventListenersModule } from 'snabbdom/modules/eventlisteners'
 import { h } from 'snabbdom/h' // helper function for creating vnodes
 import { toVNode } from 'snabbdom/tovnode'
 
-var patch = init([ // Init patch function with chosen modules
+const patch = init([ // Init patch function with chosen modules
   classModule, // makes it easy to toggle classes
   propsModule, // for setting properties on DOM elements
   styleModule, // handles styling on elements with support for animations
   eventListenersModule, // attaches event listeners
 ])
 
-var newVNode = h('div', { style: { color: '#000' } }, [
+const newVNode = h('div', { style: { color: '#000' } }, [
   h('h1', 'Headline'),
   h('p', 'A paragraph'),
 ])
@@ -319,8 +319,8 @@ To see the difference between this hook and the `remove` hook,
 consider an example.
 
 ```mjs
-var vnode1 = h('div', [h('div', [h('span', 'Hello')])])
-var vnode2 = h('div', [])
+const vnode1 = h('div', [h('div', [h('span', 'Hello')])])
+const vnode2 = h('div', [])
 patch(container, vnode1)
 patch(vnode1, vnode2)
 ```
@@ -339,7 +339,7 @@ animate the disappearance of the removed element's children.
 Modules works by registering global listeners for [hooks](#hooks). A module is simply a dictionary mapping hook names to functions.
 
 ```mjs
-var myModule = {
+const myModule = {
   create: function (oldVnode, vnode) {
     // invoked whenever a new virtual node is created
   },
@@ -564,7 +564,7 @@ In particular, you should **not** do something like this:
 
 ```mjs
 // Does not work
-var sharedHandler = {
+const sharedHandler = {
   change: function (e) { console.log('you chose: ' + e.target.value) }
 }
 h('div', [
@@ -588,7 +588,7 @@ Alternatively, simply make sure each node is passed unique `on` values:
 
 ```mjs
 // Works
-var sharedHandler = function (e) {
+const sharedHandler = function (e) {
   console.log('you chose: ' + e.target.value)
 }
 h('div', [
@@ -614,7 +614,7 @@ nodes. SVG elements are automatically created with the appropriate
 namespaces.
 
 ```mjs
-var vnode = h('div', [
+const vnode = h('div', [
   h('svg', { attrs: { width: 100, height: 100 } }, [
     h('circle', { attrs: { cx: 50, cy: 50, r: 40, stroke: 'green', 'stroke-width': 4, fill: 'yellow' } })
   ])
@@ -819,13 +819,13 @@ Uncaught NotFoundError: Failed to execute 'insertBefore' on 'Node':
 The reason for this error is reusing of vnodes between patches (see code example), snabbdom stores actual dom nodes inside the virtual dom nodes passed to it as performance improvement, so reusing nodes between patches is not supported.
 
 ```mjs
-var sharedNode = h('div', {}, 'Selected')
-var vnode1 = h('div', [
+const sharedNode = h('div', {}, 'Selected')
+const vnode1 = h('div', [
   h('div', {}, ['One']),
   h('div', {}, ['Two']),
   h('div', {}, [sharedNode]),
 ])
-var vnode2 = h('div', [
+const vnode2 = h('div', [
   h('div', {}, ['One']),
   h('div', {}, [sharedNode]),
   h('div', {}, ['Three']),
@@ -837,7 +837,7 @@ patch(vnode1, vnode2)
 You can fix this issue by creating a shallow copy of the object (here with object spread syntax):
 
 ```mjs
-var vnode2 = h('div', [
+const vnode2 = h('div', [
   h('div', {}, ['One']),
   h('div', {}, [{ ...sharedNode }]),
   h('div', {}, ['Three']),
@@ -847,8 +847,8 @@ var vnode2 = h('div', [
 Another solution would be to wrap shared vnodes in a factory function:
 
 ```mjs
-var sharedNode = () => h('div', {}, 'Selected')
-var vnode1 = h('div', [
+const sharedNode = () => h('div', {}, 'Selected')
+const vnode1 = h('div', [
   h('div', {}, ['One']),
   h('div', {}, ['Two']),
   h('div', {}, [sharedNode()]),

package.json

@@ -34,7 +34,7 @@
     "@types/lodash.shuffle": "4.2.6",
     "@types/mathjs": "6.0.5",
     "@types/mocha": "8.0.3",
-    "@typescript-eslint/eslint-plugin": "4.2.0",
+    "@typescript-eslint/eslint-plugin": "4.15.1",
     "babel-loader": "8.1.0",
     "benchmark": "2.1.4",
     "chai": "4.2.0",
@@ -42,13 +42,12 @@
     "core-js": "3.6.5",
     "cross-env": "7.0.3",
     "editorconfig-checker": "3.2.0",
-    "eslint": "7.9.0",
-    "eslint-config-standard-with-typescript": "19.0.1",
-    "eslint-plugin-import": "2.22.0",
-    "eslint-plugin-markdown": "2.0.0-rc.0",
+    "eslint": "7.20.0",
+    "eslint-config-standard-with-typescript": "20.0.0",
+    "eslint-plugin-import": "2.22.1",
+    "eslint-plugin-markdown": "2.0.0",
     "eslint-plugin-node": "11.1.0",
     "eslint-plugin-promise": "4.3.1",
-    "eslint-plugin-standard": "4.0.1",
     "faker": "5.4.0",
     "globby": "11.0.2",
     "husky": "5.0.9",

src/package/h.ts

@@ -23,10 +23,10 @@ export function h (sel: string, data: VNodeData | null): VNode
 export function h (sel: string, children: VNodeChildren): VNode
 export function h (sel: string, data: VNodeData | null, children: VNodeChildren): VNode
 export function h (sel: any, b?: any, c?: any): VNode {
-  var data: VNodeData = {}
-  var children: any
-  var text: any
-  var i: number
+  let data: VNodeData = {}
+  let children: any
+  let text: any
+  let i: number
   if (c !== undefined) {
     if (b !== null) {
       data = b

src/package/modules/attributes.ts

@@ -9,10 +9,10 @@ const colonChar = 58
 const xChar = 120
 
 function updateAttrs (oldVnode: VNode, vnode: VNode): void {
-  var key: string
-  var elm: Element = vnode.elm as Element
-  var oldAttrs = (oldVnode.data as VNodeData).attrs
-  var attrs = (vnode.data as VNodeData).attrs
+  let key: string
+  const elm: Element = vnode.elm as Element
+  let oldAttrs = (oldVnode.data as VNodeData).attrs
+  let attrs = (vnode.data as VNodeData).attrs
 
   if (!oldAttrs && !attrs) return
   if (oldAttrs === attrs) return

src/package/modules/class.ts

@@ -4,11 +4,11 @@ import { Module } from './module'
 export type Classes = Record<string, boolean>
 
 function updateClass (oldVnode: VNode, vnode: VNode): void {
-  var cur: any
-  var name: string
-  var elm: Element = vnode.elm as Element
-  var oldClass = (oldVnode.data as VNodeData).class
-  var klass = (vnode.data as VNodeData).class
+  let cur: any
+  let name: string
+  const elm: Element = vnode.elm as Element
+  let oldClass = (oldVnode.data as VNodeData).class
+  let klass = (vnode.data as VNodeData).class
 
   if (!oldClass && !klass) return
   if (oldClass === klass) return

src/package/modules/eventlisteners.ts

@@ -17,15 +17,15 @@ function invokeHandler<N extends keyof HTMLElementEventMap> (handler: SomeListen
     handler.call(vnode, event, vnode)
   } else if (typeof handler === 'object') {
     // call multiple handlers
-    for (var i = 0; i < handler.length; i++) {
+    for (let i = 0; i < handler.length; i++) {
       invokeHandler(handler[i], vnode, event)
     }
   }
 }
 
 function handleEvent (event: Event, vnode: VNode) {
-  var name = event.type
-  var on = (vnode.data as VNodeData).on
+  const name = event.type
+  const on = (vnode.data as VNodeData).on
 
   // call event handler(s) if exists
   if (on && on[name]) {
@@ -40,12 +40,12 @@ function createListener () {
 }
 
 function updateEventListeners (oldVnode: VNode, vnode?: VNode): void {
-  var oldOn = (oldVnode.data as VNodeData).on
-  var oldListener = (oldVnode as any).listener
-  var oldElm: Element = oldVnode.elm as Element
-  var on = vnode && (vnode.data as VNodeData).on
-  var elm: Element = (vnode && vnode.elm) as Element
-  var name: string
+  const oldOn = (oldVnode.data as VNodeData).on
+  const oldListener = (oldVnode as any).listener
+  const oldElm: Element = oldVnode.elm as Element
+  const on = vnode && (vnode.data as VNodeData).on
+  const elm: Element = (vnode && vnode.elm) as Element
+  let name: string
 
   // optimization for reused immutable handlers
   if (oldOn === on) {
@@ -73,7 +73,7 @@ function updateEventListeners (oldVnode: VNode, vnode?: VNode): void {
   // add new listeners which has not already attached
   if (on) {
     // reuse existing listener or create new
-    var listener = (vnode as any).listener = (oldVnode as any).listener || createListener()
+    const listener = (vnode as any).listener = (oldVnode as any).listener || createListener()
     // update vnode for listener
     listener.vnode = vnode
 

src/package/modules/hero.ts

@@ -3,8 +3,8 @@ import { Module } from './module'
 
 export type Hero = { id: string }
 
-var raf = (typeof window !== 'undefined' && window.requestAnimationFrame) || setTimeout
-var nextFrame = function (fn: any) {
+const raf = (typeof window !== 'undefined' && window.requestAnimationFrame) || setTimeout
+const nextFrame = function (fn: any) {
   raf(function () {
     raf(fn)
   })
@@ -17,9 +17,9 @@ function setNextFrame (obj: any, prop: string, val: any): void {
 }
 
 function getTextNodeRect (textNode: Text): ClientRect | undefined {
-  var rect: ClientRect | undefined
+  let rect: ClientRect | undefined
   if (document.createRange) {
-    var range = document.createRange()
+    const range = document.createRange()
     range.selectNodeContents(textNode)
     if (range.getBoundingClientRect) {
       rect = range.getBoundingClientRect()
@@ -36,8 +36,8 @@ function calcTransformOrigin (
   if (isTextNode) {
     if (textRect) {
       // calculate pixels to center of text from left edge of bounding box
-      var relativeCenterX = textRect.left + textRect.width / 2 - boundingRect.left
-      var relativeCenterY = textRect.top + textRect.height / 2 - boundingRect.top
+      const relativeCenterX = textRect.left + textRect.width / 2 - boundingRect.left
+      const relativeCenterY = textRect.top + textRect.height / 2 - boundingRect.top
       return relativeCenterX + 'px ' + relativeCenterY + 'px'
     }
   }
@@ -67,7 +67,7 @@ function isTextElement (elm: Element | Text): elm is Text {
   return elm.childNodes.length === 1 && elm.childNodes[0].nodeType === 3
 }
 
-var removed: any, created: any
+let removed: any, created: any
 
 function pre () {
   removed = {}
@@ -75,7 +75,7 @@ function pre () {
 }
 
 function create (oldVnode: VNode, vnode: VNode): void {
-  var hero = (vnode.data as VNodeData).hero
+  const hero = (vnode.data as VNodeData).hero
   if (hero && hero.id) {
     created.push(hero.id)
     created.push(vnode)
@@ -83,20 +83,20 @@ function create (oldVnode: VNode, vnode: VNode): void {
 }
 
 function destroy (vnode: VNode): void {
-  var hero = (vnode.data as VNodeData).hero
+  const hero = (vnode.data as VNodeData).hero
   if (hero && hero.id) {
-    var elm = vnode.elm;
+    const elm = vnode.elm;
     (vnode as any).isTextNode = isTextElement(elm as Element | Text); // is this a text node?
     (vnode as any).boundingRect = (elm as Element).getBoundingClientRect(); // save the bounding rectangle to a new property on the vnode
     (vnode as any).textRect = (vnode as any).isTextNode ? getTextNodeRect((elm as Element).childNodes[0] as Text) : null // save bounding rect of inner text node
-    var computedStyle = window.getComputedStyle(elm as Element, undefined); // get current styles (includes inherited properties)
+    const computedStyle = window.getComputedStyle(elm as Element, undefined); // get current styles (includes inherited properties)
     (vnode as any).savedStyle = JSON.parse(JSON.stringify(computedStyle)) // save a copy of computed style values
     removed[hero.id] = vnode
   }
 }
 
 function post () {
-  var i: number, id: any, newElm: Element, oldVnode: VNode, oldElm: Element,
+  let i: number, id: any, newElm: Element, oldVnode: VNode, oldElm: Element,
     hRatio: number, wRatio: number,
     oldRect: ClientRect, newRect: ClientRect, dx: number, dy: number,
     origTransform: string | null, origTransition: string | null,
@@ -146,11 +146,11 @@ function post () {
       setNextFrame(newStyle, 'transform', origTransform)
       setNextFrame(newStyle, 'opacity', '1')
       // Animate old element
-      for (var key in (oldVnode as any).savedStyle) { // re-apply saved inherited properties
+      for (const key in (oldVnode as any).savedStyle) { // re-apply saved inherited properties
         if (String(parseInt(key)) !== key) {
-          var ms = key.substring(0, 2) === 'ms'
-          var moz = key.substring(0, 3) === 'moz'
-          var webkit = key.substring(0, 6) === 'webkit'
+          const ms = key.substring(0, 2) === 'ms'
+          const moz = key.substring(0, 3) === 'moz'
+          const webkit = key.substring(0, 6) === 'webkit'
           if (!ms && !moz && !webkit) {
             // ignore prefixed style properties
             (oldStyle as any)[key] = (oldVnode as any).savedStyle[key]

src/package/modules/props.ts

@@ -4,12 +4,12 @@ import { Module } from './module'
 export type Props = Record<string, any>
 
 function updateProps (oldVnode: VNode, vnode: VNode): void {
-  var key: string
-  var cur: any
-  var old: any
-  var elm = vnode.elm
-  var oldProps = (oldVnode.data as VNodeData).props
-  var props = (vnode.data as VNodeData).props
+  let key: string
+  let cur: any
+  let old: any
+  const elm = vnode.elm
+  let oldProps = (oldVnode.data as VNodeData).props
+  let props = (vnode.data as VNodeData).props
 
   if (!oldProps && !props) return
   if (oldProps === props) return

src/package/modules/style.ts

@@ -7,13 +7,13 @@ export type VNodeStyle = Record<string, string> & {
 }
 
 // Bindig `requestAnimationFrame` like this fixes a bug in IE/Edge. See #360 and #409.
-var raf = (typeof window !== 'undefined' && (window.requestAnimationFrame).bind(window)) || setTimeout
-var nextFrame = function (fn: any) {
+const raf = (typeof window !== 'undefined' && (window.requestAnimationFrame).bind(window)) || setTimeout
+const nextFrame = function (fn: any) {
   raf(function () {
     raf(fn)
   })
 }
-var reflowForced = false
+let reflowForced = false
 
 function setNextFrame (obj: any, prop: string, val: any): void {
   nextFrame(function () {
@@ -22,17 +22,17 @@ function setNextFrame (obj: any, prop: string, val: any): void {
 }
 
 function updateStyle (oldVnode: VNode, vnode: VNode): void {
-  var cur: any
-  var name: string
-  var elm = vnode.elm
-  var oldStyle = (oldVnode.data as VNodeData).style
-  var style = (vnode.data as VNodeData).style
+  let cur: any
+  let name: string
+  const elm = vnode.elm
+  let oldStyle = (oldVnode.data as VNodeData).style
+  let style = (vnode.data as VNodeData).style
 
   if (!oldStyle && !style) return
   if (oldStyle === style) return
   oldStyle = oldStyle || {}
   style = style || {}
-  var oldHasDel = 'delayed' in oldStyle
+  const oldHasDel = 'delayed' in oldStyle
 
   for (name in oldStyle) {
     if (!style[name]) {
@@ -63,10 +63,10 @@ function updateStyle (oldVnode: VNode, vnode: VNode): void {
 }
 
 function applyDestroyStyle (vnode: VNode): void {
-  var style: any
-  var name: string
-  var elm = vnode.elm
-  var s = (vnode.data as VNodeData).style
+  let style: any
+  let name: string
+  const elm = vnode.elm
+  const s = (vnode.data as VNodeData).style
   if (!s || !(style = s.destroy)) return
   for (name in style) {
     (elm as any).style[name] = style[name]
@@ -74,7 +74,7 @@ function applyDestroyStyle (vnode: VNode): void {
 }
 
 function applyRemoveStyle (vnode: VNode, rm: () => void): void {
-  var s = (vnode.data as VNodeData).style
+  const s = (vnode.data as VNodeData).style
   if (!s || !s.remove) {
     rm()
     return
@@ -84,19 +84,18 @@ function applyRemoveStyle (vnode: VNode, rm: () => void): void {
     (vnode.elm as any).offsetLeft
     reflowForced = true
   }
-  var name: string
-  var elm = vnode.elm
-  var i = 0
-  var compStyle: CSSStyleDeclaration
-  var style = s.remove
-  var amount = 0
-  var applied: string[] = []
+  let name: string
+  const elm = vnode.elm
+  let i = 0
+  const style = s.remove
+  let amount = 0
+  const applied: string[] = []
   for (name in style) {
     applied.push(name);
     (elm as any).style[name] = style[name]
   }
-  compStyle = getComputedStyle(elm as Element)
-  var props = (compStyle as any)['transition-property'].split(', ')
+  const compStyle = getComputedStyle(elm as Element)
+  const props = (compStyle as any)['transition-property'].split(', ')
   for (; i < props.length; ++i) {
     if (applied.indexOf(props[i]) !== -1) amount++
   }

src/package/ts-transform-js-extension.cjs

@@ -8,12 +8,12 @@ module.exports.transform = (ctx) => (sf) => ts.visitNode(sf, (node) => {
       node.moduleSpecifier
       ? node.moduleSpecifier.getText(sf).slice(1, -1)
       : (
-        ts.isImportTypeNode(node) &&
+          ts.isImportTypeNode(node) &&
         ts.isLiteralTypeNode(node.argument) &&
         ts.isStringLiteral(node.argument.literal)
-      )
-        ? node.argument.literal.text
-        : null
+        )
+          ? node.argument.literal.text
+          : null
 
     if (originalPath === null) return node
     const pathWithExtension = originalPath.endsWith('.js')

src/test/unit/attachto.ts

@@ -4,16 +4,16 @@ import { RemoveHook } from '../../package/hooks'
 import { attachTo } from '../../package/helpers/attachto'
 import { h } from '../../package/h'
 
-var patch = init([])
+const patch = init([])
 
 describe('attachTo', function () {
-  var elm: any, vnode0: any
+  let elm: any, vnode0: any
   beforeEach(function () {
     elm = document.createElement('div')
     vnode0 = elm
   })
   it('adds element to target', function () {
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
         attachTo(elm, h('div#attached', 'Test')),
@@ -23,13 +23,13 @@ describe('attachTo', function () {
     assert.strictEqual(elm.children.length, 2)
   })
   it('updates element at target', function () {
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
         attachTo(elm, h('div#attached', 'First text')),
       ]),
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
         attachTo(elm, h('div#attached', 'New text')),
@@ -41,13 +41,13 @@ describe('attachTo', function () {
     assert.strictEqual(elm.children[0].innerHTML, 'New text')
   })
   it('element can be inserted before modal', function () {
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
         attachTo(elm, h('div#attached', 'Text')),
       ]),
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
         h('div', 'A new element'),
@@ -60,13 +60,13 @@ describe('attachTo', function () {
     assert.strictEqual(elm.children[0].innerHTML, 'Text')
   })
   it('removes element at target', function () {
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
         attachTo(elm, h('div#attached', 'First text')),
       ]),
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
       ]),
@@ -83,13 +83,13 @@ describe('attachTo', function () {
       assert.strictEqual(elm.innerHTML, 'First text')
       cb()
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
         attachTo(elm, h('div#attached', { hook: { remove: rm } }, 'First text')),
       ]),
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       h('div#wrapper', [
         h('div', 'Some element'),
       ]),

src/test/unit/attributes.ts

@@ -3,18 +3,18 @@ import { init } from '../../package/init'
 import { attributesModule } from '../../package/modules/attributes'
 import { h } from '../../package/h'
 
-var patch = init([
+const patch = init([
   attributesModule
 ])
 
 describe('attributes', function () {
-  var elm: any, vnode0: any
+  let elm: any, vnode0: any
   beforeEach(function () {
     elm = document.createElement('div')
     vnode0 = elm
   })
   it('have their provided values', function () {
-    var vnode1 = h('div', { attrs: { href: '/foo', minlength: 1, selected: true, disabled: false } })
+    const vnode1 = h('div', { attrs: { href: '/foo', minlength: 1, selected: true, disabled: false } })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.getAttribute('href'), '/foo')
     assert.strictEqual(elm.getAttribute('minlength'), '1')
@@ -23,9 +23,9 @@ describe('attributes', function () {
     assert.strictEqual(elm.hasAttribute('disabled'), false)
   })
   it('can be memoized', function () {
-    var cachedAttrs = { href: '/foo', minlength: 1, selected: true }
-    var vnode1 = h('div', { attrs: cachedAttrs })
-    var vnode2 = h('div', { attrs: cachedAttrs })
+    const cachedAttrs = { href: '/foo', minlength: 1, selected: true }
+    const vnode1 = h('div', { attrs: cachedAttrs })
+    const vnode2 = h('div', { attrs: cachedAttrs })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.getAttribute('href'), '/foo')
     assert.strictEqual(elm.getAttribute('minlength'), '1')
@@ -36,7 +36,7 @@ describe('attributes', function () {
     assert.strictEqual(elm.getAttribute('selected'), '')
   })
   it('are not omitted when falsy values are provided', function () {
-    var vnode1 = h('div', { attrs: { href: null as any, minlength: 0, value: '', title: 'undefined' } })
+    const vnode1 = h('div', { attrs: { href: null as any, minlength: 0, value: '', title: 'undefined' } })
     elm = patch(vnode0, vnode1).elm
     assert.ok(elm.hasAttribute('href'))
     assert.ok(elm.hasAttribute('minlength'))
@@ -44,7 +44,7 @@ describe('attributes', function () {
     assert.ok(elm.hasAttribute('title'))
   })
   it('are set correctly when namespaced', function () {
-    var vnode1 = h('div', { attrs: { 'xlink:href': '#foo' } })
+    const vnode1 = h('div', { attrs: { 'xlink:href': '#foo' } })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.getAttributeNS('http://www.w3.org/1999/xlink', 'href'), '#foo')
   })
@@ -53,7 +53,7 @@ describe('attributes', function () {
     elm.id = 'myId'
     elm.className = 'myClass'
     vnode0 = elm
-    var vnode1 = h('div#myId.myClass', { attrs: {} }, ['Hello'])
+    const vnode1 = h('div#myId.myClass', { attrs: {} }, ['Hello'])
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.tagName, 'DIV')
     assert.strictEqual(elm.id, 'myId')
@@ -62,7 +62,7 @@ describe('attributes', function () {
   })
   describe('boolean attribute', function () {
     it('is present and empty string if the value is truthy', function () {
-      var vnode1 = h('div', { attrs: { required: true, readonly: 1, noresize: 'truthy' } })
+      const vnode1 = h('div', { attrs: { required: true, readonly: 1, noresize: 'truthy' } })
       elm = patch(vnode0, vnode1).elm
       assert.strictEqual(elm.hasAttribute('required'), true)
       assert.strictEqual(elm.getAttribute('required'), '')
@@ -72,13 +72,13 @@ describe('attributes', function () {
       assert.strictEqual(elm.getAttribute('noresize'), 'truthy')
     })
     it('is omitted if the value is false', function () {
-      var vnode1 = h('div', { attrs: { required: false } })
+      const vnode1 = h('div', { attrs: { required: false } })
       elm = patch(vnode0, vnode1).elm
       assert.strictEqual(elm.hasAttribute('required'), false)
       assert.strictEqual(elm.getAttribute('required'), null)
     })
     it('is not omitted if the value is falsy', function () {
-      var vnode1 = h('div', { attrs: { readonly: 0, noresize: null as any } })
+      const vnode1 = h('div', { attrs: { readonly: 0, noresize: null as any } })
       elm = patch(vnode0, vnode1).elm
       assert.ok(elm.hasAttribute('readonly'))
       assert.ok(elm.hasAttribute('noresize'))
@@ -86,11 +86,11 @@ describe('attributes', function () {
   })
   describe('Object.prototype property', function () {
     it('is not considered as a boolean attribute and shouldn\'t be omitted', function () {
-      var vnode1 = h('div', { attrs: { constructor: true } })
+      const vnode1 = h('div', { attrs: { constructor: true } })
       elm = patch(vnode0, vnode1).elm
       assert.strictEqual(elm.hasAttribute('constructor'), true)
       assert.strictEqual(elm.getAttribute('constructor'), '')
-      var vnode2 = h('div', { attrs: { constructor: false } })
+      const vnode2 = h('div', { attrs: { constructor: false } })
       elm = patch(vnode0, vnode2).elm
       assert.strictEqual(elm.hasAttribute('constructor'), false)
     })

src/test/unit/dataset.ts

@@ -4,7 +4,7 @@ import { datasetModule } from '../../package/modules/dataset'
 import { init } from '../../package/init'
 import { h } from '../../package/h'
 
-var patch = init([
+const patch = init([
   datasetModule
 ])
 
@@ -15,7 +15,7 @@ describe('dataset', function () {
     }
   })
 
-  var elm: any, vnode0: any
+  let elm: any, vnode0: any
   beforeEach(function () {
     elm = document.createElement('div')
     vnode0 = elm
@@ -25,8 +25,8 @@ describe('dataset', function () {
     assert.strictEqual(elm.dataset.foo, 'foo')
   })
   it('updates dataset', function () {
-    var vnode1 = h('i', { dataset: { foo: 'foo', bar: 'bar' } })
-    var vnode2 = h('i', { dataset: { baz: 'baz' } })
+    const vnode1 = h('i', { dataset: { foo: 'foo', bar: 'bar' } })
+    const vnode2 = h('i', { dataset: { baz: 'baz' } })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.dataset.foo, 'foo')
     assert.strictEqual(elm.dataset.bar, 'bar')
@@ -35,9 +35,9 @@ describe('dataset', function () {
     assert.strictEqual(elm.dataset.foo, undefined)
   })
   it('can be memoized', function () {
-    var cachedDataset = { foo: 'foo', bar: 'bar' }
-    var vnode1 = h('i', { dataset: cachedDataset })
-    var vnode2 = h('i', { dataset: cachedDataset })
+    const cachedDataset = { foo: 'foo', bar: 'bar' }
+    const vnode1 = h('i', { dataset: cachedDataset })
+    const vnode2 = h('i', { dataset: cachedDataset })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.dataset.foo, 'foo')
     assert.strictEqual(elm.dataset.bar, 'bar')
@@ -46,7 +46,7 @@ describe('dataset', function () {
     assert.strictEqual(elm.dataset.bar, 'bar')
   })
   it('handles string conversions', function () {
-    var vnode1 = h('i', { dataset: { empty: '', dash: '-', dashed: 'foo-bar', camel: 'fooBar', integer: 0 as any, float: 0.1 as any } })
+    const vnode1 = h('i', { dataset: { empty: '', dash: '-', dashed: 'foo-bar', camel: 'fooBar', integer: 0 as any, float: 0.1 as any } })
     elm = patch(vnode0, vnode1).elm
 
     assert.strictEqual(elm.dataset.empty, '')

src/test/unit/eventlisteners.ts

@@ -5,22 +5,22 @@ import { init } from '../../package/init'
 import { eventListenersModule } from '../../package/modules/eventlisteners'
 import { h } from '../../package/h'
 
-var patch = init([
+const patch = init([
   eventListenersModule
 ])
 
 describe('event listeners', function () {
-  var elm: any, vnode0: any
+  let elm: any, vnode0: any
   beforeEach(function () {
     elm = document.createElement('div')
     vnode0 = elm
   })
   it('attaches click event handler to element', function () {
-    var result = []
+    const result = []
     function clicked (ev: Event) {
       result.push(ev)
     }
-    var vnode = h('div', { on: { click: clicked } }, [
+    const vnode = h('div', { on: { click: clicked } }, [
       h('a', 'Click my parent'),
     ])
     elm = patch(vnode0, vnode).elm
@@ -28,9 +28,9 @@ describe('event listeners', function () {
     assert.strictEqual(1, result.length)
   })
   it('does not attach new listener', function () {
-    var result: number[] = []
+    const result: number[] = []
     // function clicked(ev) { result.push(ev); }
-    var vnode1 = h('div', {
+    const vnode1 = h('div', {
       on: {
         click: function (ev) {
           result.push(1)
@@ -39,7 +39,7 @@ describe('event listeners', function () {
     }, [
       h('a', 'Click my parent'),
     ])
-    var vnode2 = h('div', {
+    const vnode2 = h('div', {
       on: {
         click: function (ev) {
           result.push(2)
@@ -55,17 +55,17 @@ describe('event listeners', function () {
     assert.deepEqual(result, [1, 2])
   })
   it('detach attached click event handler to element', function () {
-    var result: Event[] = []
+    const result: Event[] = []
     function clicked (ev: Event) {
       result.push(ev)
     }
-    var vnode1 = h('div', { on: { click: clicked } }, [
+    const vnode1 = h('div', { on: { click: clicked } }, [
       h('a', 'Click my parent'),
     ])
     elm = patch(vnode0, vnode1).elm
     elm.click()
     assert.strictEqual(1, result.length)
-    var vnode2 = h('div', { on: {} }, [
+    const vnode2 = h('div', { on: {} }, [
       h('a', 'Click my parent'),
     ])
     elm = patch(vnode1, vnode2).elm
@@ -73,7 +73,7 @@ describe('event listeners', function () {
     assert.strictEqual(1, result.length)
   })
   it('multiple event handlers for same event on same element', function () {
-    var called = 0
+    let called = 0
     function clicked (ev: Event, vnode: VNode) {
       ++called
       // Check that the first argument is an event
@@ -81,13 +81,13 @@ describe('event listeners', function () {
       // Check that the second argument was a vnode
       assert.strictEqual(vnode.sel, 'div')
     }
-    var vnode1 = h('div', { on: { click: [clicked, clicked, clicked] } }, [
+    const vnode1 = h('div', { on: { click: [clicked, clicked, clicked] } }, [
       h('a', 'Click my parent'),
     ])
     elm = patch(vnode0, vnode1).elm
     elm.click()
     assert.strictEqual(3, called)
-    var vnode2 = h('div', { on: { click: [clicked, clicked] } }, [
+    const vnode2 = h('div', { on: { click: [clicked, clicked] } }, [
       h('a', 'Click my parent'),
     ])
     elm = patch(vnode1, vnode2).elm
@@ -95,12 +95,12 @@ describe('event listeners', function () {
     assert.strictEqual(5, called)
   })
   it('access to virtual node in event handler', function () {
-    var result: VNode[] = []
+    const result: VNode[] = []
     function clicked (this: VNode, ev: Event, vnode: VNode) {
       result.push(this)
       result.push(vnode)
     }
-    var vnode1 = h('div', { on: { click: clicked } }, [
+    const vnode1 = h('div', { on: { click: clicked } }, [
       h('a', 'Click my parent'),
     ])
     elm = patch(vnode0, vnode1).elm
@@ -110,11 +110,11 @@ describe('event listeners', function () {
     assert.strictEqual(vnode1, result[1])
   })
   it('shared handlers in parent and child nodes', function () {
-    var result = []
-    var sharedHandlers = {
+    const result = []
+    const sharedHandlers = {
       click: function (ev: Event) { result.push(ev) }
     }
-    var vnode1 = h('div', { on: sharedHandlers }, [
+    const vnode1 = h('div', { on: sharedHandlers }, [
       h('a', { on: sharedHandlers }, 'Click my parent'),
     ])
     elm = patch(vnode0, vnode1).elm

src/test/unit/htmldomapi.ts

@@ -4,39 +4,39 @@ import { init } from '../../package/init'
 import { h } from '../../package/h'
 import { attributesModule } from '../../package/modules/attributes'
 
-var patch = init([
+const patch = init([
   attributesModule
 ])
 
 describe('svg', function () {
-  var elm: any, vnode0: any
+  let elm: any, vnode0: any
   beforeEach(function () {
     elm = document.createElement('svg')
     vnode0 = elm
   })
 
   it('removes child svg elements', function () {
-    var a = h('svg', {}, [
+    const a = h('svg', {}, [
       h('g'),
       h('g')
     ])
-    var b = h('svg', {}, [
+    const b = h('svg', {}, [
       h('g')
     ])
-    var result = patch(patch(vnode0, a), b).elm as SVGElement
+    const result = patch(patch(vnode0, a), b).elm as SVGElement
     assert.strictEqual(result.childNodes.length, 1)
   })
 
   it('adds correctly xlink namespaced attribute', function () {
-    var xlinkNS = 'http://www.w3.org/1999/xlink'
-    var testUrl = '/test'
-    var a = h('svg', {}, [
+    const xlinkNS = 'http://www.w3.org/1999/xlink'
+    const testUrl = '/test'
+    const a = h('svg', {}, [
       h('use', {
         attrs: { 'xlink:href': testUrl }
       }, [])
     ])
 
-    var result = patch(vnode0, a).elm as SVGElement
+    const result = patch(vnode0, a).elm as SVGElement
     assert.strictEqual(result.childNodes.length, 1)
     const child = result.childNodes[0] as SVGUseElement
     assert.strictEqual(child.getAttribute('xlink:href'), testUrl)
@@ -44,11 +44,11 @@ describe('svg', function () {
   })
 
   it('adds correctly xml namespaced attribute', function () {
-    var xmlNS = 'http://www.w3.org/XML/1998/namespace'
-    var testAttrValue = 'und'
-    var a = h('svg', { attrs: { 'xml:lang': testAttrValue } }, [])
+    const xmlNS = 'http://www.w3.org/XML/1998/namespace'
+    const testAttrValue = 'und'
+    const a = h('svg', { attrs: { 'xml:lang': testAttrValue } }, [])
 
-    var result = patch(vnode0, a).elm as SVGElement
+    const result = patch(vnode0, a).elm as SVGElement
     assert.strictEqual(result.getAttributeNS(xmlNS, 'lang'), testAttrValue)
     assert.strictEqual(result.getAttribute('xml:lang'), testAttrValue)
   })

src/test/unit/style.ts

@@ -5,7 +5,7 @@ import { styleModule } from '../../package/modules/style'
 import { h } from '../../package/h'
 import { toVNode } from '../../package/tovnode'
 
-var patch = init([
+const patch = init([
   styleModule
 ])
 
@@ -14,7 +14,7 @@ featureDiscoveryElm.style.setProperty('--foo', 'foo')
 const hasCssVariables = featureDiscoveryElm.style.getPropertyValue('--foo') === 'foo'
 
 describe('style', function () {
-  var elm: any, vnode0: any
+  let elm: any, vnode0: any
   beforeEach(function () {
     elm = document.createElement('div')
     vnode0 = elm
@@ -24,9 +24,9 @@ describe('style', function () {
     assert.strictEqual(elm.style.fontSize, '12px')
   })
   it('can be memoized', function () {
-    var cachedStyles = { fontSize: '14px', display: 'inline' }
-    var vnode1 = h('i', { style: cachedStyles })
-    var vnode2 = h('i', { style: cachedStyles })
+    const cachedStyles = { fontSize: '14px', display: 'inline' }
+    const vnode1 = h('i', { style: cachedStyles })
+    const vnode2 = h('i', { style: cachedStyles })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.style.fontSize, '14px')
     assert.strictEqual(elm.style.display, 'inline')
@@ -35,9 +35,9 @@ describe('style', function () {
     assert.strictEqual(elm.style.display, 'inline')
   })
   it('updates styles', function () {
-    var vnode1 = h('i', { style: { fontSize: '14px', display: 'inline' } })
-    var vnode2 = h('i', { style: { fontSize: '12px', display: 'block' } })
-    var vnode3 = h('i', { style: { fontSize: '10px', display: 'block' } })
+    const vnode1 = h('i', { style: { fontSize: '14px', display: 'inline' } })
+    const vnode2 = h('i', { style: { fontSize: '12px', display: 'block' } })
+    const vnode3 = h('i', { style: { fontSize: '10px', display: 'block' } })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.style.fontSize, '14px')
     assert.strictEqual(elm.style.display, 'inline')
@@ -49,9 +49,9 @@ describe('style', function () {
     assert.strictEqual(elm.style.display, 'block')
   })
   it('explicialy removes styles', function () {
-    var vnode1 = h('i', { style: { fontSize: '14px' } })
-    var vnode2 = h('i', { style: { fontSize: '' } })
-    var vnode3 = h('i', { style: { fontSize: '10px' } })
+    const vnode1 = h('i', { style: { fontSize: '14px' } })
+    const vnode2 = h('i', { style: { fontSize: '' } })
+    const vnode3 = h('i', { style: { fontSize: '10px' } })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.style.fontSize, '14px')
     patch(vnode1, vnode2)
@@ -60,9 +60,9 @@ describe('style', function () {
     assert.strictEqual(elm.style.fontSize, '10px')
   })
   it('implicially removes styles from element', function () {
-    var vnode1 = h('div', [h('i', { style: { fontSize: '14px' } })])
-    var vnode2 = h('div', [h('i')])
-    var vnode3 = h('div', [h('i', { style: { fontSize: '10px' } })])
+    const vnode1 = h('div', [h('i', { style: { fontSize: '14px' } })])
+    const vnode2 = h('div', [h('i')])
+    const vnode3 = h('div', [h('i', { style: { fontSize: '10px' } })])
     patch(vnode0, vnode1)
     assert.strictEqual(elm.firstChild.style.fontSize, '14px')
     patch(vnode1, vnode2)
@@ -74,9 +74,9 @@ describe('style', function () {
     if (!hasCssVariables) {
       this.skip()
     } else {
-      var vnode1 = h('div', { style: { '--myVar': 1 as any } })
-      var vnode2 = h('div', { style: { '--myVar': 2 as any } })
-      var vnode3 = h('div', { style: { '--myVar': 3 as any } })
+      const vnode1 = h('div', { style: { '--myVar': 1 as any } })
+      const vnode2 = h('div', { style: { '--myVar': 2 as any } })
+      const vnode3 = h('div', { style: { '--myVar': 3 as any } })
       elm = patch(vnode0, vnode1).elm
       assert.strictEqual(elm.style.getPropertyValue('--myVar'), '1')
       elm = patch(vnode1, vnode2).elm
@@ -89,9 +89,9 @@ describe('style', function () {
     if (!hasCssVariables) {
       this.skip()
     } else {
-      var vnode1 = h('i', { style: { '--myVar': 1 as any } })
-      var vnode2 = h('i', { style: { '--myVar': '' } })
-      var vnode3 = h('i', { style: { '--myVar': 2 as any } })
+      const vnode1 = h('i', { style: { '--myVar': 1 as any } })
+      const vnode2 = h('i', { style: { '--myVar': '' } })
+      const vnode3 = h('i', { style: { '--myVar': 2 as any } })
       elm = patch(vnode0, vnode1).elm
       assert.strictEqual(elm.style.getPropertyValue('--myVar'), '1')
       patch(vnode1, vnode2)
@@ -104,9 +104,9 @@ describe('style', function () {
     if (!hasCssVariables) {
       this.skip()
     } else {
-      var vnode1 = h('div', [h('i', { style: { '--myVar': 1 as any } })])
-      var vnode2 = h('div', [h('i')])
-      var vnode3 = h('div', [h('i', { style: { '--myVar': 2 as any } })])
+      const vnode1 = h('div', [h('i', { style: { '--myVar': 1 as any } })])
+      const vnode2 = h('div', [h('i')])
+      const vnode3 = h('div', [h('i', { style: { '--myVar': 2 as any } })])
       patch(vnode0, vnode1)
       assert.strictEqual(elm.firstChild.style.getPropertyValue('--myVar'), '1')
       patch(vnode1, vnode2)
@@ -116,8 +116,8 @@ describe('style', function () {
     }
   })
   it('updates delayed styles in next frame', function (done) {
-    var vnode1 = h('i', { style: { fontSize: '14px', delayed: { fontSize: '16px' } as any } })
-    var vnode2 = h('i', { style: { fontSize: '18px', delayed: { fontSize: '20px' } as any } })
+    const vnode1 = h('i', { style: { fontSize: '14px', delayed: { fontSize: '16px' } as any } })
+    const vnode2 = h('i', { style: { fontSize: '18px', delayed: { fontSize: '20px' } as any } })
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.style.fontSize, '14px')
     requestAnimationFrame(() => {
@@ -135,14 +135,14 @@ describe('style', function () {
     })
   })
   it('applies tranform as transition on remove', function (done) {
-    var btn = h('button', {
+    const btn = h('button', {
       style: {
         transition: 'transform 0.1s',
         remove: { transform: 'translateY(100%)' } as any
       }
     }, ['A button'])
-    var vnode1 = h('div.parent', {}, [btn])
-    var vnode2 = h('div.parent', {}, [null])
+    const vnode1 = h('div.parent', {}, [btn])
+    const vnode2 = h('div.parent', {}, [null])
     document.body.appendChild(vnode0)
     patch(vnode0, vnode1)
     patch(vnode1, vnode2)
@@ -155,10 +155,10 @@ describe('style', function () {
   })
   describe('using toVNode()', function () {
     it('handles (ignoring) comment nodes', function () {
-      var comment = document.createComment('yolo')
-      var prevElm = document.createElement('div')
+      const comment = document.createComment('yolo')
+      const prevElm = document.createElement('div')
       prevElm.appendChild(comment)
-      var nextVNode = h('div', [h('span', 'Hi')])
+      const nextVNode = h('div', [h('span', 'Hi')])
       elm = patch(toVNode(prevElm), nextVNode).elm
       assert.strictEqual(elm, prevElm)
       assert.strictEqual(elm.tagName, 'DIV')

src/test/unit/thunk.ts

@@ -5,11 +5,11 @@ import { h } from '../../package/h'
 import { thunk } from '../../package/thunk'
 import { VNode } from '../../package/vnode'
 
-var patch = init([
+const patch = init([
 ])
 
 describe('thunk', function () {
-  var elm: any, vnode0: any
+  let elm: any, vnode0: any
   beforeEach(function () {
     elm = vnode0 = document.createElement('div')
   })
@@ -17,21 +17,21 @@ describe('thunk', function () {
     function numberInSpan (n: number) {
       return h('span', 'Number is ' + n)
     }
-    var vnode = thunk('span', 'num', numberInSpan, [22])
+    const vnode = thunk('span', 'num', numberInSpan, [22])
     assert.deepEqual(vnode.sel, 'span')
     assert.deepEqual(vnode.data.key, 'num')
     assert.deepEqual(vnode.data.args, [22])
   })
   it('calls render function once on data change', function () {
-    var called = 0
+    let called = 0
     function numberInSpan (n: number) {
       called++
       return h('span', { key: 'num' }, 'Number is ' + n)
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       thunk('span', 'num', numberInSpan, [1])
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       thunk('span', 'num', numberInSpan, [2])
     ])
     patch(vnode0, vnode1)
@@ -40,15 +40,15 @@ describe('thunk', function () {
     assert.strictEqual(called, 2)
   })
   it('does not call render function on data unchanged', function () {
-    var called = 0
+    let called = 0
     function numberInSpan (n: number) {
       called++
       return h('span', { key: 'num' }, 'Number is ' + n)
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       thunk('span', 'num', numberInSpan, [1])
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       thunk('span', 'num', numberInSpan, [1])
     ])
     patch(vnode0, vnode1)
@@ -57,15 +57,15 @@ describe('thunk', function () {
     assert.strictEqual(called, 1)
   })
   it('calls render function once on data-length change', function () {
-    var called = 0
+    let called = 0
     function numberInSpan (n: number) {
       called++
       return h('span', { key: 'num' }, 'Number is ' + n)
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       thunk('span', 'num', numberInSpan, [1])
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       thunk('span', 'num', numberInSpan, [1, 2])
     ])
     patch(vnode0, vnode1)
@@ -74,7 +74,7 @@ describe('thunk', function () {
     assert.strictEqual(called, 2)
   })
   it('calls render function once on function change', function () {
-    var called = 0
+    let called = 0
     function numberInSpan (n: number) {
       called++
       return h('span', { key: 'num' }, 'Number is ' + n)
@@ -83,10 +83,10 @@ describe('thunk', function () {
       called++
       return h('span', { key: 'num' }, 'Number really is ' + n)
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       thunk('span', 'num', numberInSpan, [1])
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       thunk('span', 'num', numberInSpan2, [1])
     ])
     patch(vnode0, vnode1)
@@ -95,18 +95,18 @@ describe('thunk', function () {
     assert.strictEqual(called, 2)
   })
   it('renders correctly', function () {
-    var called = 0
+    let called = 0
     function numberInSpan (n: number) {
       called++
       return h('span', { key: 'num' }, 'Number is ' + n)
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       thunk('span', 'num', numberInSpan, [1])
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       thunk('span', 'num', numberInSpan, [1])
     ])
-    var vnode3 = h('div', [
+    const vnode3 = h('div', [
       thunk('span', 'num', numberInSpan, [2])
     ])
     elm = patch(vnode0, vnode1).elm
@@ -124,19 +124,19 @@ describe('thunk', function () {
     function vnodeFn (s: string) {
       return h('span.number', 'Hello ' + s)
     }
-    var vnode1 = thunk('span.number', vnodeFn, ['World!'])
+    const vnode1 = thunk('span.number', vnodeFn, ['World!'])
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.innerText, 'Hello World!')
   })
   it('renders correctly when root', function () {
-    var called = 0
+    let called = 0
     function numberInSpan (n: number) {
       called++
       return h('span', { key: 'num' }, 'Number is ' + n)
     }
-    var vnode1 = thunk('span', 'num', numberInSpan, [1])
-    var vnode2 = thunk('span', 'num', numberInSpan, [1])
-    var vnode3 = thunk('span', 'num', numberInSpan, [2])
+    const vnode1 = thunk('span', 'num', numberInSpan, [1])
+    const vnode2 = thunk('span', 'num', numberInSpan, [1])
+    const vnode3 = thunk('span', 'num', numberInSpan, [2])
 
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.tagName.toLowerCase(), 'span')
@@ -156,11 +156,11 @@ describe('thunk', function () {
       return h('span', { key: 'num' }, 'Number is ' + n)
     }
     function oddEven (n: number): VNode {
-      var prefix = (n % 2) === 0 ? 'Even' : 'Odd'
+      const prefix = (n % 2) === 0 ? 'Even' : 'Odd'
       return h('div', { key: oddEven as any }, prefix + ': ' + n)
     }
-    var vnode1 = h('div', [thunk('span', 'num', numberInSpan, [1])])
-    var vnode2 = h('div', [thunk('div', 'oddEven', oddEven, [4])])
+    const vnode1 = h('div', [thunk('span', 'num', numberInSpan, [1])])
+    const vnode2 = h('div', [thunk('div', 'oddEven', oddEven, [4])])
 
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.firstChild.tagName.toLowerCase(), 'span')
@@ -175,11 +175,11 @@ describe('thunk', function () {
       return h('span', { key: 'num' }, 'Number is ' + n)
     }
     function oddEven (n: number): VNode {
-      var prefix = (n % 2) === 0 ? 'Even' : 'Odd'
+      const prefix = (n % 2) === 0 ? 'Even' : 'Odd'
       return h('div', { key: oddEven as any }, prefix + ': ' + n)
     }
-    var vnode1 = thunk('span', 'num', numberInSpan, [1])
-    var vnode2 = thunk('div', 'oddEven', oddEven, [4])
+    const vnode1 = thunk('span', 'num', numberInSpan, [1])
+    const vnode2 = thunk('div', 'oddEven', oddEven, [4])
 
     elm = patch(vnode0, vnode1).elm
     assert.strictEqual(elm.tagName.toLowerCase(), 'span')
@@ -190,19 +190,19 @@ describe('thunk', function () {
     assert.strictEqual(elm.innerHTML, 'Even: 4')
   })
   it('invokes destroy hook on thunks', function () {
-    var called = 0
+    let called = 0
     function destroyHook () {
       called++
     }
     function numberInSpan (n: number) {
       return h('span', { key: 'num', hook: { destroy: destroyHook } }, 'Number is ' + n)
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       h('div', 'Foo'),
       thunk('span', 'num', numberInSpan, [1]),
       h('div', 'Foo')
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       h('div', 'Foo'),
       h('div', 'Foo')
     ])
@@ -211,19 +211,19 @@ describe('thunk', function () {
     assert.strictEqual(called, 1)
   })
   it('invokes remove hook on thunks', function () {
-    var called = 0
+    let called = 0
     function hook () {
       called++
     }
     function numberInSpan (n: number) {
       return h('span', { key: 'num', hook: { remove: hook } }, 'Number is ' + n)
     }
-    var vnode1 = h('div', [
+    const vnode1 = h('div', [
       h('div', 'Foo'),
       thunk('span', 'num', numberInSpan, [1]),
       h('div', 'Foo')
     ])
-    var vnode2 = h('div', [
+    const vnode2 = h('div', [
       h('div', 'Foo'),
       h('div', 'Foo')
     ])