Address a bunch of TODOs and add parameter validation everywhere

src/output.ts

@@ -32,7 +32,7 @@ export type OutputAudioTrack = OutputTrack & { type: 'audio' };
 export type OutputSubtitleTrack = OutputTrack & { type: 'subtitle' };
 
 type VideoTrackMetadata = {
-	rotation?: 0 | 90 | 180 | 270 | TransformationMatrix,
+	rotation?: 0 | 90 | 180 | 270 | TransformationMatrix, // TODO respect this field for Matroska
 	frameRate?: number
 };
 type AudioTrackMetadata = {};
@@ -46,6 +46,16 @@ export class Output {
 	finalizing = false;
 
 	constructor(options: OutputOptions) {
+		if (!options || typeof options !== 'object') {
+			throw new TypeError('options must be an object.');
+		}
+		if (!(options.format instanceof OutputFormat)) {
+			throw new TypeError('options.format must be an OutputFormat.');
+		}
+		if (!(options.target instanceof Target)) {
+			throw new TypeError('options.target must be a Target.');
+		}
+
 		if (options.target.output) {
 			throw new Error('Target is already used for another output.');
 		}
@@ -56,14 +66,51 @@ export class Output {
 	}
 
 	addVideoTrack(source: VideoSource, metadata: VideoTrackMetadata = {}) {
+		if (!(source instanceof VideoSource)) {
+			throw new TypeError('source must be a VideoSource.');
+		}
+		if (!metadata || typeof metadata !== 'object') {
+			throw new TypeError('metadata must be an object.');
+		}
+		if (typeof metadata.rotation === 'number' && ![0, 90, 180, 270].includes(metadata.rotation)) {
+			throw new TypeError(`Invalid video rotation: ${metadata.rotation}. Has to be 0, 90, 180 or 270.`);
+		} else if (
+			Array.isArray(metadata.rotation) &&
+			(metadata.rotation.length !== 9 || metadata.rotation.some(value => !Number.isFinite(value)))
+		) {
+			throw new TypeError(`Invalid video transformation matrix: ${metadata.rotation.join()}`);
+		}
+		if (
+			metadata.frameRate !== undefined &&
+			(!Number.isInteger(metadata.frameRate) || metadata.frameRate <= 0)
+		) {
+			throw new TypeError(
+				`Invalid video frame rate: ${metadata.frameRate}. Must be a positive integer.`
+			);
+		}
+
 		this.addTrack('video', source, metadata);
 	}
 
 	addAudioTrack(source: AudioSource, metadata: AudioTrackMetadata = {}) {
+		if (!(source instanceof AudioSource)) {
+			throw new TypeError('source must be an AudioSource.');
+		}
+		if (!metadata || typeof metadata !== 'object') {
+			throw new TypeError('metadata must be an object.');
+		}
+
 		this.addTrack('audio', source, metadata);
 	}
 
 	addSubtitleTrack(source: SubtitleSource, metadata: SubtitleTrackMetadata = {}) {
+		if (!(source instanceof SubtitleSource)) {
+			throw new TypeError('source must be a SubtitleSource.');
+		}
+		if (!metadata || typeof metadata !== 'object') {
+			throw new TypeError('metadata must be an object.');
+		}
+
 		this.addTrack('subtitle', source, metadata);
 	}
 
@@ -90,8 +137,6 @@ export class Output {
 	}
 
 	start() {
-		// TODO: Warn / throw if there are no sources
-
 		if (this.started) {
 			throw new Error('Output already started.');
 		}
@@ -105,8 +150,6 @@ export class Output {
 	}
 
 	async finalize() {
-		// TODO: Test what happens when finalizing without a single chunk of media
-
 		if (this.finalizing) {
 			throw new Error('Cannot call finalize twice.');
 		}