Using file-saver package for better cross-browser support.

package.json

@@ -3,9 +3,11 @@
   "version": "1.0.0",
   "main": "src/index.tsx",
   "dependencies": {
+    "canvas-toBlob": "^1.0.0",
     "canvg": "^1.5.3",
     "d3": "^5.7.0",
     "detect-browser": "^4.1.0",
+    "file-saver": "^2.0.1",
     "history": "^4.7.2",
     "md5": "^2.2.1",
     "query-string": "^5.1.1",
@@ -19,6 +21,7 @@
   },
   "devDependencies": {
     "@types/d3": "^5.5.0",
+    "@types/file-saver": "^2.0.0",
     "@types/history": "^4.7.2",
     "@types/jest": "*",
     "@types/md5": "^2.1.33",