fix: restructure to use only 1 assertion

Author: gagik

src/deferred-promise.ts

@@ -13,19 +13,11 @@ export class DeferredPromise<T> extends Promise<T> {
         executor: (resolve: (value: T) => void, reject: (reason: Error) => void) => void,
         { timeout, onTimeout }: DeferredPromiseOptions<T> = {}
     ) {
-        let resolveFn: (value: T) => void;
-        let rejectFn: (reason?: unknown) => void;
-
         super((resolve, reject) => {
-            resolveFn = resolve;
-            rejectFn = reject;
+            this.resolve = resolve;
+            this.reject = reject;
         });
 
-        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-        this.resolve = resolveFn!;
-        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-        this.reject = rejectFn!;
-
         if (timeout !== undefined && onTimeout) {
             this.timeoutId = setTimeout(() => {
                 onTimeout(this.resolve, this.reject);