Fix linting and add new lint rules

src/export/packer/next-compiler.spec.ts

@@ -25,7 +25,7 @@ describe("Compiler", () => {
     });
 
     describe("#compile()", () => {
-        it("should pack all the content", async function () {
+        it("should pack all the content", function () {
             this.timeout(99999999);
             const file = new File({
                 sections: [],
@@ -53,7 +53,7 @@ describe("Compiler", () => {
             expect(fileNames).to.include("_rels/.rels");
         });
 
-        it("should pack all additional headers and footers", async function () {
+        it("should pack all additional headers and footers", function () {
             const file = new File({
                 sections: [
                     {

src/export/packer/packer.spec.ts

@@ -54,7 +54,7 @@ describe("Packer", () => {
             assert.isTrue(buffer.byteLength > 0);
         });
 
-        it("should handle exception if it throws any", async () => {
+        it("should handle exception if it throws any", () => {
             // eslint-disable-next-line @typescript-eslint/no-explicit-any
             const compiler = stub((Packer as any).compiler, "compile");
 
@@ -139,7 +139,7 @@ describe("Packer", () => {
             const stream = await Packer.toStream(file);
             return new Promise((resolve, reject) => {
                 stream.on("error", () => {
-                    reject();
+                    reject(new Error());
                 });
 
                 stream.on("end", () => {
@@ -148,7 +148,7 @@ describe("Packer", () => {
             });
         });
 
-        it("should handle exception if it throws any", async () => {
+        it("should handle exception if it throws any", () => {
             // eslint-disable-next-line @typescript-eslint/no-explicit-any
             const compiler = stub((Packer as any).compiler, "compile").callsFake(() => ({
                 // tslint:disable-next-line: no-empty
@@ -160,9 +160,11 @@ describe("Packer", () => {
             }));
 
             compiler.throwsException();
-            return Packer.toStream(file).catch((error) => {
+            try {
+                Packer.toStream(file);
+            } catch (error) {
                 assert.isDefined(error);
-            });
+            }
         });
 
         afterEach(() => {

src/export/packer/packer.ts

@@ -58,7 +58,7 @@ export class Packer {
         return zipData;
     }
 
-    public static async toStream(file: File, prettify?: boolean | PrettifyType): Promise<Stream> {
+    public static toStream(file: File, prettify?: boolean | PrettifyType): Stream {
         const zip = this.compiler.compile(file, prettify);
         const zipData = zip.generateNodeStream({
             type: "nodebuffer",