feat: add format function

[jaulz]

Sometimes you want to modify the name of the migration (e.g. in my case I would like to remove the file suffix because it changes depending on whether I run the Typescript or compiled version). This PR introduces a format function in the options that takes care of it.

[kf6kjg]

Watch your whitespace, that's what's causing the CI to fail. Otherwise this looks good to me and would allow me to solve the same problem.

However I'd go one step further and provide a way to format the name that is in storage too. That way I can take an existing database that was migrated without a formatter and still not have a migration collision. You could use the same format function, it would just force the user to add additional logic. Or you can have different functions for each side: one for formatting files from disk, another for formatting migration names from storage.

[papb]

Hi @jaulz, thanks for the PR! Please address my comments and also address the suggestion by @kf6kjg. Thanks!

[jaulz]

Thanks for your input! I just pushed the updated files.

@kf6kjg do you mean something like this?
https://github.com/sequelize/umzug/pull/196/files#diff-410142b027abfe35d3351577b731ebcaR106-R107

[kf6kjg]

Yeah, that looks like it should work. I like it. It'd be good to give an example of how to use the option in the documentation such as

{
  nameFormatter: path => {
    const filename = Path.basename(path); // Isolate the file name from the full path.
    return filename.slice(0, filename.lastIndexOf(".")); // Remove the file extension, leaving just the unique name of the migration.
  }
}

At least that's what I'd use as I have migrations being run under Node on the live server at the moment and I'd like to eventually change over to using Node-TS, thus dropping the whole extra compile-to-JS step. This would prevent the extension change, .js to .ts, from causing any headaches.

[kf6kjg]

Though, reviewing the code a little, I think it'd be good for you to write up some unit tests to exercise this. Also to make sure to fix whatever's causing the existing unit tests to fail - but I suspect you are already on top of that! :D

[jaulz]

@kf6kjg okay, it's ready 😊

[papb]

Nice! Just one more thing, please take a look at our current readme and see if this feature should be mentioned somewhere. For example, I think it should be mentioned in this section - please take a look if it should be also mentioned somewhere else. Thanks!

[jaulz]

Okay, I added it including the example of the file extension removal.