[].forEach((key) => {
  data[key]("foo")
    .then(() => console.log("bar"))
    .catch(() => console.log("baz"));
});

[].forEach((key) => {
  data("foo")
    [key]("bar")
    .then(() => console.log("bar"))
    .catch(() => console.log("baz"));
});

window.Data[key]("foo")
  .then(() => a)
  .catch(() => b);