Emoji Encoding and Decoding erlang from list to binary

Question

I want this string to be parsed for VOIP Notification for iOS to binary string:

"{\"data\":{\"text\":\"❤️\"}}"

I expected the data printed on the Erlang shell to be:

<<"{\"data\":{\"text\":\"❤️\"}}">>

But when printed it shows:

{"data",[{"text",[10084,65039]}]}

I tried the solution from Encoding emoji in Erlang but it just gives me a bit string of the emoji which is:

{<<"data">>,{[{<<"text">>,<<100,39,15,254>>}]}}

How do I properly show it in Unicode in the Erlang shell?

Answer 1

In the first example you provide it is properly encoded, but it is not properly displayed. When you define strings using double quotes the string is actually stored as a list of character codes. In the case of the heart emoji [10084,65039] are the character codes. The Erlang shell isn't printing out the emoji itself, but rather the values of the bytes that represent the emoji.

In the second case, a binary string, you shouldn't need to do any special encoding of the binary, but you will need to tell Erlang to treat it as a UTF8 string. You can do that by specifying /utf8 at the end before the closing >>:

<<"{\"data\":{\"text\":\"❤️\"}}"/utf8>>.

If you want to see the emoji stored in strings and binaries like these displayed in the shell as actual emoji and not character codes, you will need to use the +pc option when starting the shell so it treats all unicode characters as printable characters:

erl +pc unicode

Setting it to unicode will cause emoji printed in the shell like this:

http://erlang.org/doc/man/erl.html#id201195