Mobx: Repeated When

[Amareis]

I have a Idea. There is common pattern in my reactions:
reaction(() => client.online, online => online && ts.sync()).
Basically, it's just when, which is not autodisposes itself on first run. So, it can be done via when option named (e.g.) repeated. With it, my code will look as:
when(() => client.online, () => ts.sync(), {repeated: true})

• [X] What problem would it solve for you?
  Code readability and complexity.
• [X] Do you think others will benefit from this change as well and it should in core package (see also mobx-utils)?
  Yep, it just additional when option, which can be useful for many cases.
• [X] Are you willing to (attempt) a PR yourself?
  Maybe, it shouldn't be difficult.

[mweststrate]

I think the syntactical sugar here is so straight-forward that it doesn't
justify expanding the api for it. Rather, it confuses two concepts which
are now clearly deliniated: one time? -> when. Multiple times? -> reaction

Op di 29 jan. 2019 om 14:44 schreef Иван Плесских <[email protected]

:

I have a Idea. There is common pattern in my reactions:
reaction(() => client.online, online => online && ts.sync()).
Basically, it's just when, which is not autodisposes itself on first run.
So, it can be done via when option named (e.g.) repeated. With it, my
code will look as:
when(() => client.online, () => ts.sync(), {repeated: true})

• What problem would it solve for you?
  Code readability and complexity.
• Do you think others will benefit from this change as well and it
  should in core package (see also mobx-utils)?
  Yep, it just additional when option, which can be useful for many
  cases.
• Are you willing to (attempt) a PR yourself?
  Maybe, it shouldn't be difficult.

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[Amareis]

Hmm. My second approach was reactionWhen, which is can be added to mobx-utils.

[nunocastromartins]

My two cents: call it whenever and just declare it yourself:

function whenever(whenFn: () => boolean, doFn: () => void): () => void {
  return reaction(whenFn, val => val && doFn());
}

Example usage:

 whenever(() => client.online, () => ts.sync());

[mweststrate]

Closing, the pattern is hopefully so straight forward I don't see any need to standardize this

[mweststrate]

Thanks for sharing the idea nonetheless!

[lock[bot]]

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