util-lola:
[ This description is mirrored from README.md at github.com/manufosela/util-lola on 2019-05-22 ]
util-lola 
Polymer component based in (LoLa (loading layer)) GitHub - manufosela/LoLa: javascript Loading Layer
Use
Put the component in your polymer app.
- active value attribute to show Loading Layer
- message value to show in Layer
- timeout value if you want to close in that seconds.
Change active attribute to false in a callback to close the Loading Layer when all process has loaded.
<util-lola active="true" timeout="2" message="2 seconds demo and it will close itself"></util-lola>