toLocaleString support

[ranquild]

Please add toLocaleString method to num as it is in JS. I am aware that there is NumberFormat class in intl package however toLocaleString api is more convenient to use.

[Aetet]

Any progress on this @kevmoo ?

[kevmoo]

@lrhn thoughts on this?

[matanlurey]

I personally would like to see this as an enhancement to package:intl - i.e. start having intl use the browser where polyfills aren't required. This might require extension method support in Dart to make it easier though.

[lrhn]

I would probably prefer to not have "locale" in the platform libraries, and keep all of it in package:intl.

Adding a num.toLocaleString suggets also adding a DateTime.toLocaleString and other locale relevant formatting functions. These would be functions that already exist in package:intl.
If the platform tells us that the locale's LC_NUMERIC is en_US.UTF-8, we still need a way to translate that symbolic name into an actual format, so it could require the full generality of package:intl anyway.

The advantage to putting something into the platform libraries is that maybe it can use OS provided functions to do the work (or at least specify the format), and not need the full intl library, but that makes it an embedder issue - anyone implementing Dart on a platform needs to provide these. If some platform can't provide this information or functionality, then the user is worse off than if there was no toLocaleString.

Obviously JavaScript has the functions for Number and Date, and most OS's has too, so it's not impossible.

[alan-knight]

I don't think it's at all feasible to put it into the platform libraries. These functions are very complicated, it would add a lot of work for any embedder. Putting it into package intl would also be problematic. For the same reasons, they really can't be done portably, and the behavior does not match the existing Intl mechanisms for these - the locale names are different, the formats are specified entirely differently, and the options are not the same. They're also not uniformly available on all supported browsers.

By far the simplest thing would be provide a separate package that makes these available via Js interop. That would also make it much easier to update and for people to add pieces. I did a very very rough first pass at this, and will publish it once the appropriate rituals are complete.

[p30arena]

I'm still waiting for a progress