refactor(common): ensure compatibility with typescript strict flag (#30993)

As part of FW-1265, the `@angular/common` package is made compatible
with the TypeScript `--strict` flag. Read more about the strict flag [here](https://www.typescriptlang.org/docs/handbook/compiler-options.html)

PR Close #30993

packages/common/http/src/xhr.ts

@@ -231,7 +231,7 @@ export class HttpXhrBackend implements HttpBackend {
       // The onError callback is called when something goes wrong at the network level.
       // Connection timeout, DNS error, offline, etc. These are actual errors, and are
       // transmitted on the error channel.
-      const onError = (error: ErrorEvent) => {
+      const onError = (error: ProgressEvent) => {
         const {url} = partialFromXhr();
         const res = new HttpErrorResponse({
           error,

packages/common/src/directives/ng_for_of.ts

@@ -216,15 +216,18 @@ export class NgForOf<T> implements DoCheck {
   private _applyChanges(changes: IterableChanges<T>) {
     const insertTuples: RecordViewTuple<T>[] = [];
     changes.forEachOperation(
-        (item: IterableChangeRecord<any>, adjustedPreviousIndex: number, currentIndex: number) => {
+        (item: IterableChangeRecord<any>, adjustedPreviousIndex: number | null,
+         currentIndex: number | null) => {
           if (item.previousIndex == null) {
             const view = this._viewContainer.createEmbeddedView(
-                this._template, new NgForOfContext<T>(null !, this._ngForOf, -1, -1), currentIndex);
+                this._template, new NgForOfContext<T>(null !, this._ngForOf, -1, -1),
+                currentIndex === null ? undefined : currentIndex);
             const tuple = new RecordViewTuple<T>(item, view);
             insertTuples.push(tuple);
           } else if (currentIndex == null) {
-            this._viewContainer.remove(adjustedPreviousIndex);
-          } else {
+            this._viewContainer.remove(
+                adjustedPreviousIndex === null ? undefined : adjustedPreviousIndex);
+          } else if (adjustedPreviousIndex !== null) {
             const view = this._viewContainer.get(adjustedPreviousIndex) !;
             this._viewContainer.move(view, currentIndex);
             const tuple = new RecordViewTuple(item, <EmbeddedViewRef<NgForOfContext<T>>>view);

packages/common/src/i18n/format_date.ts

@@ -378,7 +378,7 @@ function weekGetter(size: number, monthBased = false): DateFormatter {
   };
 }
 
-type DateFormatter = (date: Date, locale: string, offset?: number) => string;
+type DateFormatter = (date: Date, locale: string, offset: number) => string;
 
 const DATE_FORMATS: {[format: string]: DateFormatter} = {};
 

packages/upgrade/src/common/src/angular1.ts

@@ -117,8 +117,7 @@ export interface ITranscludeFunction {
   (cloneAttachFn?: ICloneAttachFunction): IAugmentedJQuery;
 }
 export interface ICloneAttachFunction {
-  // Let's hint but not force cloneAttachFn's signature
-  (clonedElement?: IAugmentedJQuery, scope?: IScope): any;
+  (clonedElement: IAugmentedJQuery, scope: IScope): any;
 }
 export type IAugmentedJQuery = Node[] & {
   on?: (name: string, fn: () => void) => void;