Adjust some types

ts/types/Attachment.ts

@@ -168,13 +168,10 @@ export type AttachmentDraftType =
       size: number;
     };
 
-export type ThumbnailType = {
-  height?: number;
-  width?: number;
-  url?: string;
-  contentType: MIME.MIMEType;
-  path?: string;
-  data?: Uint8Array;
+export type ThumbnailType = Pick<
+  AttachmentType,
+  'height' | 'width' | 'url' | 'contentType' | 'path' | 'data'
+> & {
   // Only used when quote needed to make an in-memory thumbnail
   objectUrl?: string;
 };
@@ -236,7 +233,7 @@ export async function migrateDataToFileSystem(
 // Over time, we can expand this definition to become more narrow, e.g. require certain
 // fields, etc.
 export function isValid(
-  rawAttachment?: AttachmentType
+  rawAttachment?: Pick<AttachmentType, 'data' | 'path'>
 ): rawAttachment is AttachmentType {
   // NOTE: We cannot use `_.isPlainObject` because `rawAttachment` is
   // deserialized by protobuf:
@@ -396,14 +393,14 @@ export function hasData(attachment: AttachmentType): boolean {
 
 export function loadData(
   readAttachmentData: (path: string) => Promise<Uint8Array>
-): (attachment: AttachmentType) => Promise<AttachmentWithHydratedData> {
+): (
+  attachment: Pick<AttachmentType, 'data' | 'path'>
+) => Promise<AttachmentWithHydratedData> {
   if (!is.function_(readAttachmentData)) {
     throw new TypeError("'readAttachmentData' must be a function");
   }
 
-  return async (
-    attachment: AttachmentType
-  ): Promise<AttachmentWithHydratedData> => {
+  return async attachment => {
     if (!isValid(attachment)) {
       throw new TypeError("'attachment' is not valid");
     }