Hi all! I would like to ask for an ideas how to solve the different way JavaScript and Elixir are approaching Strings and indexes of characters. I want to store the same (user entered) text on the Elixir and also the JavaScript side. I also want to exchange messages describing operations like {:de…

Operate on bytes it is the safest way, so you do not use String module in short. This will provide you independence form encoding of your data. So it would look like this // JavaScript message to Elixir, somebody wrote "áb" ["insert", 0, Uint8Array.of(97, 204, 129, 98)] // JavaScript message to Eli…

Unicode is hard. Unicode is very hard. Unicode is enormously hard. If you want to have consistent behaviour then operate on bytes. So you will use Blob or Uint8Array on JS side and binaries on Elixir side. I think it would be the simplest way. I hope that what you are describing (as I assume you…

Thank you for your reply @hauleth . I am not sure I understand your solution. I will try to write pseudo-code example: // JavaScript message to Elixir, somebody wrote "áb" {:insert, 0, String.fromCharCode(97, 769, 98)} // JavaScript message to Elixir, somebody deleted "á" (but not b) {:delete, 0, 2…

The big question is, do you want to work on “graphemes” or on “codepoints”? If the latter, do you do normalize first? The Javascript seems to operate on “codepoints”, though the current normalisation is unknown, if it normalises at all, instead of just taking what it gets from the operating system. …

:slight_smile: I want to work on whatever is simpler and more consistent or safe respectively. I don’t do any normalization (yet?). But maybe it will be necessary. I am not sure. That’s why I am asking. I don’t want to overcomplicate it.

Do you want to be a and ^ be considered as separate or as â? If the latter, work on graphemes. Read docs of string functions carefully to know if they work on graphemes or codepoints. The same is true for the JS functions and methods you use. Though I have to disappoint you. It will be complicat…

Thanks a lot. Now I understand. :+1:

I tried to do a little benchmark here and I am quite surprised, that doing binary_part(binary, from, length) is 46x faster than Enum.slice(charlist, from, to) Of course doing String.slice(string, from, to) is extremely slow. That’s not surprising. Do you have some tips to do that even faster?

[image] stefanluptak: Do you have some tips to do that even faster? Do what, binary_part? binary_part is about as fast as it gets on the BEAM for that specific operation I think.

Yes, I meant that one. Sorry for not being clear enough. OK, good to know. Thanks. :ok_hand:

Binaries are in reality just byte arrays and binary_part is just make_binary(old + start, length), so I highly doubt that you can get any faster than that.

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JS/Elixir string indexing interoperability

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stefanluptak April 19, 2020, 1:35pm 8

Thanks a lot. Now I understand.