Enable strict

js/canvas1.ts

@@ -22,8 +22,8 @@ import type { byte } from './types';
  */
 
 export class TextPage {
-  _page: ImageData;
+  _page: ImageData | undefined;
-  _context: CanvasRenderingContext2D;
+  _context: CanvasRenderingContext2D | undefined;
 
   _buffer: byte[][] = [];
   _greenMode = false;
@@ -98,6 +98,9 @@ export class TextPage {
     this.refresh();
   }
   writeAt(row: byte, col: byte, val: byte): void {
+    if (!this._page) {
+      return;
+    }
     this._buffer[row][col] = val;
     const data = this._page.data;
     let color;
@@ -169,6 +172,9 @@ export class TextPage {
     this.refresh();
   }
   blit() {
+    if (!this._page || !this._context) {
+      return;
+    }
     if (this._dirty) {
       this._context.putImageData(
         this._page,

js/ui/keyboard.ts

@@ -214,19 +214,17 @@ export class KeyBoard {
       return span;
     }
 
-    const _mouseup = (
+    const _mouseup = (event: Event) => {
-      event: MouseEvent & {
+      if (!(event.currentTarget instanceof HTMLElement)) {
-        currentTarget: HTMLElement;
+        return;
       }
-    ) => {
       event.currentTarget.classList.remove('pressed');
     };
 
-    const _mousedown = (
+    const _mousedown = (event: Event) => {
-      event: MouseEvent & {
+      if (!(event.currentTarget instanceof HTMLElement)) {
-        currentTarget: HTMLElement;
+        return;
       }
-    ) => {
       event.currentTarget.classList.add('pressed');
       let key = event.currentTarget.dataset[this.shifted ? 'key2' : 'key1'];
       if (!key) {
@@ -262,7 +260,7 @@ export class KeyBoard {
           case 'SHIFT':
             this.shifted = !this.shifted;
             this.kb
-              .querySelectorAll('.key-SHIFT')
+              .querySelectorAll<HTMLElement>('.key-SHIFT')
               .forEach(function (el: HTMLElement) {
                 el.classList.toggle('active');
               });

tsconfig.json

@@ -8,15 +8,13 @@
     "allowSyntheticDefaultImports": true,
     "target": "es6",
     "lib": ["DOM", "ES6"],
-    "noImplicitAny": true,
+    "strict": true,
-    "noImplicitThis": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
     "exactOptionalPropertyTypes": true,
     "moduleResolution": "node",
     "resolveJsonModule": true,
     "sourceMap": true,
-    "strictNullChecks": true,
     "outDir": "dist",
     "baseUrl": ".",
     "allowJs": true,