feat: Export collection as direct download instead of emailing (#1001)

* feat: Export collection as zip instead of emailing

* Flow typing download.js

app/utils/download.js

@@ -0,0 +1,146 @@
+// @flow
+/* global navigator */
+
+// download.js v3.0, by dandavis; 2008-2014. [CCBY2] see http://danml.com/download.html for tests/usage
+// v1 landed a FF+Chrome compat way of downloading strings to local un-named files, upgraded to use a hidden frame and optional mime
+// v2 added named files via a[download], msSaveBlob, IE (10+) support, and window.URL support for larger+faster saves than dataURLs
+// v3 added dataURL and Blob Input, bind-toggle arity, and legacy dataURL fallback was improved with force-download mime and base64 support
+
+// data can be a string, Blob, File, or dataURL
+
+export default function download(
+  data: Blob | string | File,
+  strFileName: string,
+  strMimeType?: string
+) {
+  var self = window, // this script is only for browsers anyway...
+    u = 'application/octet-stream', // this default mime also triggers iframe downloads
+    m = strMimeType || u,
+    x = data,
+    D = document,
+    a = D.createElement('a'),
+    z = function(a, o) {
+      return String(a);
+    },
+    B = self.Blob || self.MozBlob || self.WebKitBlob || z,
+    BB = self.MSBlobBuilder || self.WebKitBlobBuilder || self.BlobBuilder,
+    fn = strFileName || 'download',
+    blob,
+    b,
+    fr;
+
+  if (String(this) === 'true') {
+    //reverse arguments, allowing download.bind(true, "text/xml", "export.xml") to act as a callback
+    x = [x, m];
+    m = x[0];
+    x = x[1];
+  }
+
+  //go ahead and download dataURLs right away
+  if (String(x).match(/^data\:[\w+\-]+\/[\w+\-]+[,;]/)) {
+    // $FlowIssue
+    return navigator.msSaveBlob // IE10 can't do a[download], only Blobs:
+      ? // $FlowIssue
+        navigator.msSaveBlob(d2b(x), fn)
+      : saver(x); // everyone else can save dataURLs un-processed
+  } //end if dataURL passed?
+
+  try {
+    blob = x instanceof B ? x : new B([x], { type: m });
+  } catch (y) {
+    if (BB) {
+      b = new BB();
+      b.append([x]);
+      blob = b.getBlob(m); // the blob
+    }
+  }
+
+  function d2b(u) {
+    if (typeof u !== 'string') {
+      throw Error('Attempted to pass non-string to d2b');
+    }
+    var p = u.split(/[:;,]/),
+      t = p[1],
+      dec = p[2] === 'base64' ? atob : decodeURIComponent,
+      bin = dec(p.pop()),
+      mx = bin.length,
+      i = 0,
+      uia = new Uint8Array(mx);
+
+    for (i; i < mx; ++i) uia[i] = bin.charCodeAt(i);
+
+    return new B([uia], { type: t });
+  }
+
+  function saver(url, winMode) {
+    if (typeof url !== 'string') {
+      throw Error('Attempted to pass non-string url to saver');
+    }
+
+    if ('download' in a) {
+      a.href = url;
+      a.setAttribute('download', fn);
+      a.innerHTML = 'downloading…';
+      D.body && D.body.appendChild(a);
+      setTimeout(function() {
+        a.click();
+        D.body && D.body.removeChild(a);
+        if (winMode === true) {
+          setTimeout(function() {
+            self.URL.revokeObjectURL(a.href);
+          }, 250);
+        }
+      }, 66);
+      return true;
+    }
+
+    //do iframe dataURL download (old ch+FF):
+    var f = D.createElement('iframe');
+    D.body && D.body.appendChild(f);
+    if (!winMode) {
+      // force a mime that will download:
+      url = 'data:' + url.replace(/^data:([\w\/\-\+]+)/, u);
+    }
+
+    f.src = url;
+    setTimeout(function() {
+      D.body && D.body.removeChild(f);
+    }, 333);
+  }
+
+  // $FlowIssue
+  if (navigator.msSaveBlob) {
+    // IE10+ : (has Blob, but not a[download] or URL)
+    return navigator.msSaveBlob(blob, fn);
+  }
+
+  if (self.URL) {
+    // simple fast and modern way using Blob and URL:
+    saver(self.URL.createObjectURL(blob), true);
+  } else {
+    // handle non-Blob()+non-URL browsers:
+    if (
+      blob &&
+      (typeof blob === 'string' || blob.constructor === z) &&
+      typeof m === 'string'
+    ) {
+      try {
+        return saver('data:' + m + ';base64,' + self.btoa(blob));
+      } catch (y) {
+        // $FlowIssue
+        return saver('data:' + m + ',' + encodeURIComponent(blob));
+      }
+    }
+
+    // Blob but not URL:
+    fr = new FileReader();
+    fr.onload = function(e) {
+      saver(this.result);
+    };
+
+    if (blob instanceof Blob) {
+      fr.readAsDataURL(blob);
+    }
+  }
+  return true;
+}