Show file size in download button tooltip

Adds the dataset file size to the download button tooltip, so hovering
shows something like "Download (1.5 GB)" instead of just "Download".
Uses the existing bytesToString formatter. Falls back to plain
"Download" for empty or zero-size datasets.

Author: dannon

client/src/components/History/Content/Dataset/DatasetDownload.test.ts

@@ -8,8 +8,8 @@ import DatasetDownload from "./DatasetDownload.vue";
 const localVue = getLocalVue();
 
 const items = [
-    { id: "item_id", extension: "ext", meta_files: [{ file_type: "a" }, { file_type: "b" }] },
-    { id: "item_id", extension: "ext", meta_files: [] },
+    { id: "item_id", extension: "ext", file_size: 1024, meta_files: [{ file_type: "a" }, { file_type: "b" }] },
+    { id: "item_id", extension: "ext", file_size: 0, meta_files: [] },
 ];
 
 describe("DatasetDownload", () => {

client/src/components/History/Content/Dataset/DatasetDownload.vue

@@ -6,6 +6,7 @@ import { computed } from "vue";
 
 import type { HDADetailed } from "@/api";
 import { prependPath } from "@/utils/redirect";
+import { bytesToString } from "@/utils/utils";
 
 interface Props {
     item: HDADetailed;
@@ -27,6 +28,13 @@ const metaDownloadUrl = computed(() => {
 const downloadUrl = computed(() => {
     return prependPath(`api/datasets/${props.item.id}/display?to_ext=${props.item.extension}`);
 });
+const downloadTitle = computed(() => {
+    const size = props.item.file_size;
+    if (size) {
+        return `Download (${bytesToString(size)})`;
+    }
+    return "Download";
+});
 
 function onDownload(resource: string, extension = "") {
     emit("on-download", `${resource}${extension}`);
@@ -43,7 +51,7 @@ function onDownload(resource: string, extension = "") {
         size="sm"
         variant="link"
         toggle-class="text-decoration-none"
-        title="Download"
+        :title="downloadTitle"
         class="download-btn"
         data-description="dataset download">
         <template v-slot:button-content>
@@ -68,7 +76,7 @@ function onDownload(resource: string, extension = "") {
         v-else
         v-g-tooltip.hover
         class="download-btn px-1"
-        title="Download"
+        :title="downloadTitle"
         size="sm"
         variant="link"
         :href="downloadUrl"