type Variant = { kind: "video_mp4"; size: number; key: string; }; type PlaybackInput = { originalMimeType: string | null | undefined; variants: Variant[]; }; export function pickVideoPlaybackVariant(input: PlaybackInput): | { kind: "video_mp4"; size: number } | { kind: "original" } { const mp4Variant = input.variants.find( (variant) => variant.kind === "video_mp4" && variant.size === 720, ); if (mp4Variant) { return { kind: "video_mp4", size: mp4Variant.size }; } return { kind: "original" }; }