Fix element type hierarchy

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@creatomate/preview",
-  "version": "1.1.1",
+  "version": "1.2.0",
   "description": "Render video and image previews in your web app prior to creating a final MP4, GIF, JPEG or PNG through the API.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

src/AudioState.ts

@@ -1,4 +1,6 @@
-export interface AudioState {
+import { ElementState } from './ElementState';
+
+export interface AudioState extends ElementState {
   /**
    * Audio element property. The total length of the media file used in the element.
    */

src/CompositionState.ts

@@ -1,6 +1,6 @@
 import { ElementState } from './ElementState';
 
-export interface CompositionState {
+export interface CompositionState extends ElementState {
   /**
    * Composition element property. The elements in the composition.
    */

src/ElementState.ts

@@ -1,9 +1,4 @@
-import { CompositionState } from './CompositionState';
-import { TextState } from './TextState';
-import { VideoState } from './VideoState';
-import { AudioState } from './AudioState';
-
-export interface ElementState extends CompositionState, TextState, VideoState, AudioState {
+export interface ElementState {
   /**
    * This element's track number.
    */

src/Preview.ts

@@ -1,6 +1,7 @@
 import { v4 as uuid } from 'uuid';
 import { PreviewState } from './PreviewState';
 import { ElementState } from './ElementState';
+import { CompositionState } from './CompositionState';
 
 export class Preview {
   /**
@@ -261,8 +262,8 @@ export class Preview {
           return element;
         }
 
-        if (element.elements) {
-          const foundNestedElement = this.findElement(predicate, element);
+        if ('elements' in element) {
+          const foundNestedElement = this.findElement(predicate, element as CompositionState);
           if (foundNestedElement) {
             return foundNestedElement;
           }

src/TextState.ts

@@ -1,4 +1,6 @@
-export interface TextState {
+import { ElementState } from './ElementState';
+
+export interface TextState extends ElementState {
   /**
    * Text element property. The fixed or auto-calculated font size of the text element.
    */

src/VideoState.ts

@@ -1,4 +1,6 @@
-export interface VideoState {
+import { ElementState } from './ElementState';
+
+export interface VideoState extends ElementState {
   /**
    * Video element property. The total length of the media file used in the element.
    */