download multiple files on safari ios

app/javascript/elements/download_button.js

@@ -18,27 +18,64 @@ export default targetable(class extends HTMLElement {
     this.toggleState()
 
     fetch(this.dataset.src).then((response) => response.json()).then((urls) => {
-      const fileRequests = urls.map((url) => {
-        return () => {
-          return fetch(url).then(async (resp) => {
-            const blobUrl = URL.createObjectURL(await resp.blob())
-            const link = document.createElement('a')
+      const isSafariIos = /iPhone|iPad|iPod/i.test(navigator.userAgent)
 
-            link.href = blobUrl
-            link.setAttribute('download', decodeURI(url.split('/').pop()))
+      if (isSafariIos && urls.length > 1) {
+        this.downloadSafariIos(urls)
+      } else {
+        this.downloadUrls(urls)
+      }
+    })
+  }
+
+  downloadUrls (urls) {
+    const fileRequests = urls.map((url) => {
+      return () => {
+        return fetch(url).then(async (resp) => {
+          const blobUrl = URL.createObjectURL(await resp.blob())
+          const link = document.createElement('a')
+
+          link.href = blobUrl
+          link.setAttribute('download', decodeURI(url.split('/').pop()))
+
+          link.click()
+
+          URL.revokeObjectURL(blobUrl)
+        })
+      }
+    })
 
-            link.click()
+    fileRequests.reduce(
+      (prevPromise, request) => prevPromise.then(() => request()),
+      Promise.resolve()
+    )
 
-            URL.revokeObjectURL(url)
-          })
-        }
+    this.toggleState()
+  }
+
+  downloadSafariIos (urls) {
+    const fileRequests = urls.map((url) => {
+      return fetch(url).then(async (resp) => {
+        const blob = await resp.blob()
+        const blobUrl = URL.createObjectURL(blob.slice(0, blob.size, 'application/octet-stream'))
+        const link = document.createElement('a')
+
+        link.href = blobUrl
+        link.setAttribute('download', decodeURI(url.split('/').pop()))
+
+        return link
       })
+    })
 
-      fileRequests.reduce(
-        (prevPromise, request) => prevPromise.then(() => request()),
-        Promise.resolve()
-      )
+    Promise.all(fileRequests).then((links) => {
+      links.forEach((link, index) => {
+        setTimeout(() => {
+          link.click()
 
+          URL.revokeObjectURL(link.href)
+        }, index * 50)
+      })
+    }).finally(() => {
       this.toggleState()
     })
   }

app/javascript/submission_form/completed.vue

@@ -179,27 +179,62 @@ export default {
       this.isDownloading = true
 
       fetch(this.baseUrl + `/submitters/${this.submitterSlug}/download`).then((response) => response.json()).then((urls) => {
-        const fileRequests = urls.map((url) => {
-          return () => {
-            return fetch(url).then(async (resp) => {
-              const blobUrl = URL.createObjectURL(await resp.blob())
-              const link = document.createElement('a')
+        const isSafariIos = /iPhone|iPad|iPod/i.test(navigator.userAgent)
 
-              link.href = blobUrl
-              link.setAttribute('download', decodeURI(url.split('/').pop()))
+        if (isSafariIos && urls.length > 1) {
+          this.downloadSafariIos(urls)
+        } else {
+          this.downloadUrls(urls)
+        }
+      })
+    },
+    downloadUrls (urls) {
+      const fileRequests = urls.map((url) => {
+        return () => {
+          return fetch(url).then(async (resp) => {
+            const blobUrl = URL.createObjectURL(await resp.blob())
+            const link = document.createElement('a')
+
+            link.href = blobUrl
+            link.setAttribute('download', decodeURI(url.split('/').pop()))
+
+            link.click()
+
+            URL.revokeObjectURL(blobUrl)
+          })
+        }
+      })
 
-              link.click()
+      fileRequests.reduce(
+        (prevPromise, request) => prevPromise.then(() => request()),
+        Promise.resolve()
+      )
 
-              URL.revokeObjectURL(url)
-            })
-          }
+      this.isDownloading = false
+    },
+    downloadSafariIos (urls) {
+      const fileRequests = urls.map((url) => {
+        return fetch(url).then(async (resp) => {
+          const blob = await resp.blob()
+          const blobUrl = URL.createObjectURL(blob.slice(0, blob.size, 'application/octet-stream'))
+          const link = document.createElement('a')
+
+          link.href = blobUrl
+          link.setAttribute('download', decodeURI(url.split('/').pop()))
+
+          return link
         })
+      })
 
-        fileRequests.reduce(
-          (prevPromise, request) => prevPromise.then(() => request()),
-          Promise.resolve()
-        )
+      Promise.all(fileRequests).then((links) => {
+        links.forEach((link, index) => {
+          setTimeout(() => {
+            link.click()
 
+            URL.revokeObjectURL(link.href)
+          }, index * 50)
+        })
+      }).finally(() => {
         this.isDownloading = false
       })
     }