fix: ts errors

Author: jacekkarczmarczyk

packages/vuetify/src/components/VBadge/VBadge.ts

@@ -53,13 +53,13 @@ export default mixins(
         name: 'show',
         value: this.isActive
       }]
-    }), this.$slots.badge)] : null
+    }), this.$slots.badge)] : undefined
 
     return h('span', {
       staticClass: 'v-badge',
       'class': this.classes
     }, [
-      this.$slots.default,
+      this.$slots.default!,
       h('transition', {
         props: {
           name: this.transition,

packages/vuetify/src/components/VBtn/VBtn.ts

@@ -119,7 +119,7 @@ export default baseMixins.extend<options>().extend({
       return this.$createElement(
         'div',
         { 'class': 'v-btn__content' },
-        [this.$slots.default]
+        [this.$slots.default!]
       )
     },
     genLoader (): VNode {

packages/vuetify/src/components/VChip/VChip.ts

@@ -63,7 +63,7 @@ export default mixins(Colorable, Themeable, Toggleable).extend({
       ])
     },
     genContent (h: CreateElement): VNode {
-      const children: VNodeChildren = [this.$slots.default]
+      const children: VNodeChildren = [this.$slots.default!]
 
       this.close && children.push(this.genClose(h))
 

packages/vuetify/src/components/VHover/VHover.ts

@@ -47,7 +47,7 @@ export default mixins(
 
     if (this.$scopedSlots.default) {
       element = this.$scopedSlots.default({ hover: this.isActive })
-    } else if (this.$slots.default.length === 1) {
+    } else if (this.$slots.default && this.$slots.default.length === 1) {
       element = this.$slots.default[0]
     }
 

packages/vuetify/src/components/VProgressCircular/VProgressCircular.ts

@@ -131,7 +131,7 @@ export default mixins(Colorable).extend({
   },
 
   render (h): VNode {
-    const info = h('div', { staticClass: 'v-progress-circular__info' }, [this.$slots.default])
+    const info = h('div', { staticClass: 'v-progress-circular__info' }, [this.$slots.default!])
     const svg = this.genSvg(h)
 
     return h('div', this.setTextColor(this.color, {

packages/vuetify/src/components/VTimeline/VTimelineItem.ts

@@ -80,7 +80,7 @@ export default mixins(
     genOpposite () {
       return this.$createElement('div', {
         staticClass: 'v-timeline-item__opposite'
-      }, [this.$slots.opposite])
+      }, [this.$slots.opposite!])
     }
   },