formatDuration: Include undefined values if formatting with zero option set to true

[tommaso-sebastianelli]

If I provide format values in FormatDurationOptions and set zero to true, I'm expecting also undefined Duration values to be considered in the output.

Example

Input

formatDuration(
  {
    seconds: 10,
  },
  {
    format: ["hours", "minutes", "seconds"],
    zero: true,
  }

Actual output:

10 seconds

Expected output:

Since I've explicitly set hours, minutes, and seconds I'm expecting to see them as 0 in the output.

0 hours 0 minutes 10 seconds

Note: It seems this was working like expected in 2.x but it is not working anymore in 3.x.
If this is the wanted behaviour instead, I suggest to update the relative doc in order to avoid misleading interpretations of zero param.

[kossnocorp]

Hey! I hate to say it, but merging the PR will break the function for anyone using zero right now. Additionally, the Duration doesn't allow undefined to be set as property (I realize that not all use TypeScript and set exactOptionalPropertyTypes).

Said that, breaking the function behavior was not a good idea to begin with, but let's work with what we have.

Let's hide this behavior behind an option. I feel like strict sounds the best as what you expect is to formatDuration strictly follow the format and print all units.

The docs can also be more explicit; I would appreciate it if you could update them as well.

What do you think?

[kossnocorp]

Let's hide it behind an option, see my comment: #3703 (comment)