Problem:

We have multiple functions that are pretty similar, with a minor difference. So it would be great to get rid of the duplicated code.

async function createUser(user: User): Promise<void> {
  LoadingService.startLoading();
  await userHttpClient.createUser(user);
  LoadingService.stopLoading();
  UserGrid.reloadData();
}

async function updateUser(user: User): Promise<void> {
  LoadingService.startLoading();
  await userHttpClient.updateUser(user);
  LoadingService.stopLoading();
  UserGrid.reloadData();
}

Solution:

We can extract the code that changes and pass it through the callback. In such a manner, we’ll remove duplicate code.

async function makeUserAction(fn: Function): Promise<void> {
  LoadingService.startLoading();
  await fn();
  LoadingService.stopLoading();
  UserGrid.reloadData();
}

async function createUser2(user: User): Promise<void> {
  makeUserAction(() => userHttpClient.createUser(user));
}

async function updateUser2(user: User): Promise<void> {
  makeUserAction(() => userHttpClient.updateUser(user));
}