diff --git a/src/runtime/blockdom/block_compiler.ts b/src/runtime/blockdom/block_compiler.ts
index e67d7132..460caef4 100644
--- a/src/runtime/blockdom/block_compiler.ts
+++ b/src/runtime/blockdom/block_compiler.ts
@@ -306,7 +306,7 @@ interface IndexedLocation extends Location {
 
 interface Child {
   parentRefIdx: number;
-  afterRefIdx?: number;
+  afterRefIdx: number;
   isOnlyChild?: boolean;
 }
 
@@ -374,6 +374,7 @@ function updateCtx(ctx: BlockCtx, tree: IntermediateTree) {
           // tree is the parentnode here
           ctx.children[info.idx] = {
             parentRefIdx: info.refIdx!,
+            afterRefIdx: 0,
             isOnlyChild: true,
           };
         } else {
@@ -568,7 +569,7 @@ function createBlockClass(template: HTMLElement, ctx: BlockCtx): BlockClass {
       }
 
       // applying data to all update points
-      if (locN) {
+      if (locN !== 0) {
         const data = this.data!;
         for (let i = 0; i < locN; i++) {
           const loc = locations[i];
@@ -579,13 +580,14 @@ function createBlockClass(template: HTMLElement, ctx: BlockCtx): BlockClass {
       nodeInsertBefore.call(parent, el, afterNode);
 
       // preparing all children
-      if (childN) {
+      if (childN !== 0) {
         const children = this.children;
         for (let i = 0; i < childN; i++) {
           const child = children![i];
-          if (child) {
+          if (child !== undefined) {
             const loc = childrenLocs[i];
-            const afterNode = loc.afterRefIdx ? refs[loc.afterRefIdx] : null;
+            const afterRefIdx = loc.afterRefIdx;
+            const afterNode = afterRefIdx !== 0 ? refs[afterRefIdx] : null;
             child.isOnlyChild = loc.isOnlyChild;
             child.mount(refs[loc.parentRefIdx] as any, afterNode);
           }
@@ -601,7 +603,7 @@ function createBlockClass(template: HTMLElement, ctx: BlockCtx): BlockClass {
       }
       const refs = this.refs!;
       // update texts/attributes/
-      if (locN) {
+      if (locN !== 0) {
         const data1 = this.data!;
         const data2 = other.data!;
         for (let i = 0; i < locN; i++) {
@@ -616,14 +618,14 @@ function createBlockClass(template: HTMLElement, ctx: BlockCtx): BlockClass {
       }
 
       // update children
-      if (childN) {
+      if (childN !== 0) {
         let children1 = this.children;
         const children2 = other.children;
         for (let i = 0; i < childN; i++) {
           const child1 = children1![i];
           const child2 = children2![i];
-          if (child1) {
-            if (child2) {
+          if (child1 !== undefined) {
+            if (child2 !== undefined) {
               child1.patch(child2, withBeforeRemove);
             } else {
               if (withBeforeRemove) {
@@ -632,9 +634,10 @@ function createBlockClass(template: HTMLElement, ctx: BlockCtx): BlockClass {
               child1.remove();
               children1![i] = undefined;
             }
-          } else if (child2) {
+          } else if (child2 !== undefined) {
             const loc = childrenLocs[i];
-            const afterNode = loc.afterRefIdx ? refs[loc.afterRefIdx] : null;
+            const afterRefIdx = loc.afterRefIdx;
+            const afterNode = afterRefIdx !== 0 ? refs[afterRefIdx] : null;
             child2.mount(refs[loc.parentRefIdx] as any, afterNode);
             children1![i] = child2;
           }
diff --git a/src/runtime/blockdom/events.ts b/src/runtime/blockdom/events.ts
index 9a6c7338..65406052 100644
--- a/src/runtime/blockdom/events.ts
+++ b/src/runtime/blockdom/events.ts
@@ -41,7 +41,7 @@ function createElementHandler(evName: string, capture: boolean = false): EventHa
   }
 
   function remove(this: HTMLElement) {
-    delete (this as any)[eventKey];
+    (this as any)[eventKey] = false;
     this.removeEventListener(evName, listener, { capture });
   }
   function update(this: HTMLElement, data: any) {
diff --git a/src/runtime/blockdom/list.ts b/src/runtime/blockdom/list.ts
index d3db6722..ed99a2b1 100644
--- a/src/runtime/blockdom/list.ts
+++ b/src/runtime/blockdom/list.ts
@@ -28,7 +28,7 @@ class VList {
     this.anchor = _anchor;
     nodeInsertBefore.call(parent, _anchor, afterNode);
     const l = children.length;
-    if (l) {
+    if (l !== 0) {
       const mount = children[0].mount;
       for (let i = 0; i < l; i++) {
         mount.call(children[i], parent, _anchor);
@@ -186,7 +186,7 @@ class VList {
       } else {
         for (let i = startIdx1; i <= endIdx1; i++) {
           let ch = ch1[i];
-          if (ch) {
+          if (ch !== null) {
             if (withBeforeRemove) {
               beforeRemove.call(ch);
             }
@@ -200,7 +200,7 @@ class VList {
   beforeRemove() {
     const children = this.children;
     const l = children.length;
-    if (l) {
+    if (l !== 0) {
       const beforeRemove = children[0].beforeRemove;
       for (let i = 0; i < l; i++) {
         beforeRemove.call(children[i]);
@@ -215,7 +215,7 @@ class VList {
     } else {
       const children = this.children;
       const l = children.length;
-      if (l) {
+      if (l !== 0) {
         const remove = children[0].remove;
         for (let i = 0; i < l; i++) {
           remove.call(children[i]);
@@ -240,7 +240,7 @@ export function list(children: VNode[]): VNode<VList> {
 }
 
 function createMapping(ch1: any[], startIdx1: number, endIdx2: number): { [key: string]: any } {
-  let mapping: any = {};
+  const mapping: any = {};
   for (let i = startIdx1; i <= endIdx2; i++) {
     mapping[ch1[i].key] = i;
   }
diff --git a/src/runtime/blockdom/multi.ts b/src/runtime/blockdom/multi.ts
index 9fad5fff..60fbddda 100644
--- a/src/runtime/blockdom/multi.ts
+++ b/src/runtime/blockdom/multi.ts
@@ -26,7 +26,7 @@ export class VMulti {
     const anchors = new Array(l);
     for (let i = 0; i < l; i++) {
       let child = children[i];
-      if (child) {
+      if (child !== undefined) {
         child.mount(parent, afterNode);
       } else {
         const childAnchor = document.createTextNode("");
@@ -44,7 +44,7 @@ export class VMulti {
     const anchors = this.anchors;
     for (let i = 0, l = children.length; i < l; i++) {
       let child = children[i];
-      if (child) {
+      if (child !== undefined) {
         child.moveBeforeDOMNode(node, parent);
       } else {
         const anchor = anchors![i];
@@ -56,14 +56,14 @@ export class VMulti {
   moveBeforeVNode(other: VMulti | null, afterNode: Node | null) {
     if (other) {
       const next = other!.children[0];
-      afterNode = (next ? next.firstNode() : other!.anchors![0]) || null;
+      afterNode = (next !== undefined ? next.firstNode() : other!.anchors![0]) || null;
     }
     const children = this.children;
     const parent = this.parentEl;
     const anchors = this.anchors;
     for (let i = 0, l = children.length; i < l; i++) {
       let child = children[i];
-      if (child) {
+      if (child !== undefined) {
         child.moveBeforeVNode(null, afterNode);
       } else {
         const anchor = anchors![i];
@@ -83,8 +83,8 @@ export class VMulti {
     for (let i = 0, l = children1.length; i < l; i++) {
       const vn1 = children1[i];
       const vn2 = children2[i];
-      if (vn1) {
-        if (vn2) {
+      if (vn1 !== undefined) {
+        if (vn2 !== undefined) {
           vn1.patch(vn2, withBeforeRemove);
         } else {
           const afterNode = vn1.firstNode()!;
@@ -97,7 +97,7 @@ export class VMulti {
           vn1.remove();
           children1[i] = undefined;
         }
-      } else if (vn2) {
+      } else if (vn2 !== undefined) {
         children1[i] = vn2;
         const anchor = anchors[i];
         vn2.mount(parentEl, anchor);
@@ -110,7 +110,7 @@ export class VMulti {
     const children = this.children;
     for (let i = 0, l = children.length; i < l; i++) {
       const child = children[i];
-      if (child) {
+      if (child !== undefined) {
         child.beforeRemove();
       }
     }
@@ -125,7 +125,7 @@ export class VMulti {
       const anchors = this.anchors;
       for (let i = 0, l = children.length; i < l; i++) {
         const child = children[i];
-        if (child) {
+        if (child !== undefined) {
           child.remove();
         } else {
           nodeRemoveChild.call(parentEl, anchors![i]);
@@ -136,7 +136,7 @@ export class VMulti {
 
   firstNode(): Node | undefined {
     const child = this.children[0];
-    return child ? child.firstNode() : this.anchors![0];
+    return child !== undefined ? child.firstNode() : this.anchors![0];
   }
 
   toString(): string {
diff --git a/src/runtime/template_helpers.ts b/src/runtime/template_helpers.ts
index 239e1029..5d93b1b9 100644
--- a/src/runtime/template_helpers.ts
+++ b/src/runtime/template_helpers.ts
@@ -30,7 +30,7 @@ function callSlot(
   const slots = ctx.props.slots || {};
   const { __render, __ctx, __scope } = slots[name] || {};
   const slotScope = ObjectCreate(__ctx || {});
-  if (__scope) {
+  if (__scope !== undefined) {
     slotScope[__scope] = extra;
   }
   const slotBDom = __render ? __render(slotScope, parent, key) : null;
diff --git a/src/runtime/utils.ts b/src/runtime/utils.ts
index 143e76d8..640f41e0 100644
--- a/src/runtime/utils.ts
+++ b/src/runtime/utils.ts
@@ -11,7 +11,7 @@ export type Callback = () => void;
 export function batched(callback: Callback): Callback {
   let scheduled = false;
   return async (...args) => {
-    if (!scheduled) {
+    if (scheduled === false) {
       scheduled = true;
       await Promise.resolve();
       scheduled = false;