npm install --save @tatchi/bs-idb-keyval

{
  ...
  "bs-dependencies": ["@tatchi/bs-idb-keyval"]
}

let store = IdbKeyVal.createStore("custom-db-name", "custom-store-name");

IdbKeyVal.set("key", "value", store)
  |> Js.Promise.then_(() => {
       Js.log("It worked!");
       Js.Promise.resolve();
     })
  |> Js.Promise.catch(err => {
       Js.log2("It failed!!", err);
       Js.Promise.resolve();
     });

IdbKeyVal.get("key", store)
|> Js.Promise.then_(value => {
     // logs: "value"
     Js.log(value);
     Js.Promise.resolve();
   });

IdbKeyVal.keys(store)
|> Js.Promise.then_(keys => {
     // logs: ["key"]
     Js.log(keys);
     Js.Promise.resolve();
   });

IdbKeyVal.delete("key", store)
|> Js.Promise.then_(keys => {
     Js.log("deleted");
     Js.Promise.resolve();
   });

IdbKeyVal.clear(store)
|> Js.Promise.then_(keys => {
     Js.log("cleared");
     Js.Promise.resolve();
   });