diff --git a/webapp/src/blocks/boardView.ts b/webapp/src/blocks/boardView.ts
index 789fb55b9..e42847b3e 100644
--- a/webapp/src/blocks/boardView.ts
+++ b/webapp/src/blocks/boardView.ts
@@ -10,7 +10,7 @@ type ISortOption = { propertyId: '__title' | string, reversed: boolean }
 
 interface BoardView extends IBlock {
     readonly viewType: IViewType
-    readonly groupById: string
+    readonly groupById?: string
     readonly sortOptions: readonly ISortOption[]
     readonly visiblePropertyIds: readonly string[]
     readonly visibleOptionIds: readonly string[]
@@ -20,7 +20,7 @@ interface BoardView extends IBlock {
     readonly columnWidths: Readonly<Record<string, number>>
 }
 
-class MutableBoardView extends MutableBlock {
+class MutableBoardView extends MutableBlock implements BoardView {
     get viewType(): IViewType {
         return this.fields.viewType
     }
diff --git a/webapp/src/pages/boardPage.tsx b/webapp/src/pages/boardPage.tsx
index ba8be87b4..c0616fc30 100644
--- a/webapp/src/pages/boardPage.tsx
+++ b/webapp/src/pages/boardPage.tsx
@@ -11,6 +11,7 @@ import {OctoListener} from '../octoListener'
 import {Utils} from '../utils'
 import {MutableWorkspaceTree, WorkspaceTree} from '../viewModel/workspaceTree'
 import {IBlock} from '../blocks/block'
+import { isReturnStatement } from 'typescript'
 
 type Props = {
     setLanguage: (lang: string) => void
@@ -24,18 +25,13 @@ type State = {
 }
 
 export default class BoardPage extends React.Component<Props, State> {
-    view: BoardView
-
-    updateTitleTimeout: number
-    updatePropertyLabelTimeout: number
-
     private workspaceListener = new OctoListener()
 
     constructor(props: Props) {
         super(props)
         const queryString = new URLSearchParams(window.location.search)
-        const boardId = queryString.get('id')
-        const viewId = queryString.get('v')
+        const boardId = queryString.get('id') || ''
+        const viewId = queryString.get('v') || ''
 
         this.state = {
             boardId,
@@ -180,7 +176,7 @@ export default class BoardPage extends React.Component<Props, State> {
             this.setState({
                 boardTree,
                 boardId,
-                viewId: boardTree.activeView.id,
+                viewId: boardTree.activeView!.id,
             })
             Utils.log(`sync complete: ${boardTree.board.id} (${boardTree.board.title})`)
         }
@@ -220,7 +216,7 @@ export default class BoardPage extends React.Component<Props, State> {
     }
 
     showView(viewId: string, boardId: string = this.state.boardId): void {
-        if (this.state.boardId === boardId) {
+        if (this.state.boardTree && this.state.boardId === boardId) {
             const newBoardTree = this.state.boardTree.mutableCopy()
             newBoardTree.setActiveView(viewId)
             this.setState({boardTree: newBoardTree, viewId})
@@ -233,6 +229,11 @@ export default class BoardPage extends React.Component<Props, State> {
     }
 
     setSearchText(text?: string): void {
+        if (!this.state.boardTree) {
+            Utils.assertFailure('setSearchText: boardTree')
+            return
+        }
+
         const newBoardTree = this.state.boardTree.mutableCopy()
         newBoardTree.setSearchText(text)
         this.setState({boardTree: newBoardTree})
diff --git a/webapp/src/viewModel/boardTree.ts b/webapp/src/viewModel/boardTree.ts
index 4e05a4a43..1fe0493ca 100644
--- a/webapp/src/viewModel/boardTree.ts
+++ b/webapp/src/viewModel/boardTree.ts
@@ -146,10 +146,10 @@ class MutableBoardTree implements BoardTree {
         this.cards = this.sortCards(this.cards) as MutableCard[]
         Utils.assert(this.cards !== undefined)
 
-        if (this.activeView.groupById) {
+        if (this.activeView?.groupById) {
             this.setGroupByProperty(this.activeView.groupById)
         } else {
-            Utils.assert(this.activeView.viewType !== 'board')
+            Utils.assert(this.activeView?.viewType !== 'board')
         }
 
         Utils.assert(this.cards !== undefined)
@@ -186,6 +186,10 @@ class MutableBoardTree implements BoardTree {
 
     private groupCards() {
         const {activeView, groupByProperty} = this
+        if (!activeView || !groupByProperty) {
+            Utils.assertFailure('groupCards')
+            return
+        }
 
         const unassignedOptionIds = groupByProperty.options.
             filter((o) => !activeView.visibleOptionIds.includes(o.id) && !activeView.hiddenOptionIds.includes(o.id)).
@@ -221,7 +225,7 @@ class MutableBoardTree implements BoardTree {
                 // Empty group
                 const emptyGroupCards = this.cards.filter((o) => {
                     const optionId = o.properties[groupByProperty.id]
-                    return !optionId || !this.groupByProperty.options.find((option) => option.id === optionId)
+                    return !optionId || !groupByProperty.options.find((option) => option.id === optionId)
                 })
                 const group: Group = {
                     option: {id: '', value: `No ${groupByProperty.name}`, color: ''},
@@ -264,9 +268,7 @@ class MutableBoardTree implements BoardTree {
         return cardA.createAt - cardB.createAt
     }
 
-    private manualOrder(cardA: Card, cardB: Card) {
-        const {activeView} = this
-
+    private manualOrder(activeView: BoardView, cardA: Card, cardB: Card) {
         const indexA = activeView.cardOrder.indexOf(cardA.id)
         const indexB = activeView.cardOrder.indexOf(cardB.id)
 
@@ -280,17 +282,17 @@ class MutableBoardTree implements BoardTree {
     }
 
     private sortCards(cards: Card[]): Card[] {
-        if (!this.activeView) {
+        const {board, activeView} = this
+        if (!activeView) {
             Utils.assertFailure()
             return cards
         }
-        const {board} = this
-        const {sortOptions} = this.activeView
+        const {sortOptions} = activeView
         let sortedCards: Card[] = []
 
         if (sortOptions.length < 1) {
             Utils.log('Manual sort')
-            sortedCards = cards.sort((a, b) => this.manualOrder(a, b))
+            sortedCards = cards.sort((a, b) => this.manualOrder(activeView, a, b))
         } else {
             sortOptions.forEach((sortOption) => {
                 if (sortOption.propertyId === Constants.titleColumnId) {
diff --git a/webapp/src/viewModel/cardTree.ts b/webapp/src/viewModel/cardTree.ts
index 5ddafd20c..43eaf77dc 100644
--- a/webapp/src/viewModel/cardTree.ts
+++ b/webapp/src/viewModel/cardTree.ts
@@ -5,7 +5,6 @@ import {IOrderedBlock} from '../blocks/orderedBlock'
 import octoClient from '../octoClient'
 import {IBlock, MutableBlock} from '../blocks/block'
 import {OctoUtils} from '../octoUtils'
-import {Utils} from '../utils'
 
 interface CardTree {
     readonly card: Card
@@ -17,7 +16,7 @@ interface CardTree {
 }
 
 class MutableCardTree implements CardTree {
-    card: MutableCard
+    card!: MutableCard
     comments: IBlock[] = []
     contents: IOrderedBlock[] = []