feat(media): extract workspace package

packages/media/src/dimensions.ts

@@ -0,0 +1,59 @@
+export interface MediaDimensions {
+  height: number
+  width: number
+}
+
+const METADATA_TIMEOUT_MS = 10_000
+
+function waitForDimensions(
+  file: File,
+  element: HTMLImageElement | HTMLVideoElement,
+  successEvent: "load" | "loadedmetadata"
+): Promise<MediaDimensions | undefined> {
+  return new Promise((resolve) => {
+    const objectUrl = URL.createObjectURL(file)
+    let settled = false
+    const timeout = window.setTimeout(finish, METADATA_TIMEOUT_MS)
+
+    function finish(dimensions?: MediaDimensions) {
+      if (settled) return
+      settled = true
+      window.clearTimeout(timeout)
+      URL.revokeObjectURL(objectUrl)
+      resolve(dimensions)
+    }
+
+    element.addEventListener(
+      successEvent,
+      () => {
+        const width =
+          element instanceof HTMLVideoElement
+            ? element.videoWidth
+            : element.naturalWidth
+        const height =
+          element instanceof HTMLVideoElement
+            ? element.videoHeight
+            : element.naturalHeight
+        finish(width > 0 && height > 0 ? { height, width } : undefined)
+      },
+      { once: true }
+    )
+    element.addEventListener("error", () => finish(), { once: true })
+    element.src = objectUrl
+  })
+}
+
+/** Reads intrinsic dimensions before an adapter uploads an image or video. */
+export function readMediaDimensions(
+  file: File
+): Promise<MediaDimensions | undefined> {
+  if (file.type.startsWith("image/")) {
+    return waitForDimensions(file, new Image(), "load")
+  }
+  if (file.type.startsWith("video/")) {
+    const video = document.createElement("video")
+    video.preload = "metadata"
+    return waitForDimensions(file, video, "loadedmetadata")
+  }
+  return Promise.resolve(undefined)
+}