fix: add strict true to tsconfig (#4286)

Author: Matt Goo

packages/mdc-dom/ponyfill.ts

@@ -35,7 +35,7 @@ function closest(element: Element, selector: string): Element | null {
     return element.closest(selector);
   }
 
-  let el = element;
+  let el: Element | null = element;
   while (el) {
     if (matches(el, selector)) {
       return el;

packages/mdc-linear-progress/foundation.ts

@@ -21,7 +21,7 @@
  * THE SOFTWARE.
  */
 
-import {getCorrectPropertyName, StandardCssPropertyName} from '@material/animation';
+import {getCorrectPropertyName, StandardCssPropertyName} from '@material/animation/index';
 import MDCFoundation from '@material/base/foundation';
 import {MDCLinearProgressAdapter} from './adapter';
 import {cssClasses, strings} from './constants';
@@ -48,9 +48,9 @@ export default class MDCLinearProgressFoundation extends MDCFoundation<MDCLinear
     };
   }
 
-  private isDeterminate_: boolean;
-  private isReversed_: boolean;
-  private progress_: number;
+  private isDeterminate_!: boolean;
+  private isReversed_!: boolean;
+  private progress_!: number;
 
   init() {
     this.isDeterminate_ = !this.adapter_.hasClass(cssClasses.INDETERMINATE_CLASS);

tsconfig.json

@@ -1,12 +1,19 @@
 {
   "compilerOptions": {
     "lib": ["es5", "es6", "dom"],
-    "noEmitOnError": true,
-    "noImplicitAny": true,
-    "noImplicitThis": true,
+    "downlevelIteration": true,
+    "moduleResolution": "node",
+    "experimentalDecorators": true,
+    "emitDecoratorMetadata": true,
+    "skipLibCheck": true,
+    "noFallthroughCasesInSwitch": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
-    "alwaysStrict": true,
+    "noErrorTruncation": true,
+    "noEmitOnError": false,
+    "importHelpers": true,
+    "noStrictGenericChecks": true,
+    "strict": true,
     "pretty": true,
     "preserveConstEnums": true,
     "stripInternal": true,