Introduce some functional programming techniques

src/file/media/data.ts

@@ -1,20 +1,20 @@
 export interface IMediaDataDimensions {
-    pixels: {
-        x: number;
-        y: number;
+    readonly pixels: {
+        readonly x: number;
+        readonly y: number;
     };
-    emus: {
-        x: number;
-        y: number;
+    readonly emus: {
+        readonly x: number;
+        readonly y: number;
     };
 }
 
 export interface IMediaData {
-    referenceId: number;
-    stream: Buffer | Uint8Array | ArrayBuffer;
-    path?: string;
-    fileName: string;
-    dimensions: IMediaDataDimensions;
+    readonly referenceId: number;
+    readonly stream: Buffer | Uint8Array | ArrayBuffer;
+    readonly path?: string;
+    readonly fileName: string;
+    readonly dimensions: IMediaDataDimensions;
 }
 
 // Needed because of: https://github.com/s-panferov/awesome-typescript-loader/issues/432

src/file/media/media.ts

@@ -5,6 +5,7 @@ import { IMediaData } from "./data";
 import { Image } from "./image";
 
 interface IHackedFile {
+    // tslint:disable-next-line:readonly-keyword
     currentRelationshipId: number;
 }
 
@@ -78,17 +79,15 @@ export class Media {
     private createMedia(
         key: string,
         relationshipsCount: number,
-        dimensions: { width: number; height: number },
+        dimensions: { readonly width: number; readonly height: number },
         data: Buffer | string | Uint8Array | ArrayBuffer,
         filePath?: string,
     ): IMediaData {
-        if (typeof data === "string") {
-            data = this.convertDataURIToBinary(data);
-        }
+        const newData = typeof data === "string" ? this.convertDataURIToBinary(data) : data;
 
-        const imageData = {
+        const imageData: IMediaData = {
             referenceId: relationshipsCount,
-            stream: data,
+            stream: newData,
             path: filePath,
             fileName: key,
             dimensions: {