[SOLVED] How to remove all but emojis in a (Javascript) string?

How to remove all but emojis in a (Javascript) string?

I'm trying multiple RegEx expressions but I cannot get them to work.

I have a simple input where the users can type whatever they like, only that the final result must contain emojis. To achieve this, I have to remove every character from the string which is not an emoji, and then check if the length is >= 1.

So basically this: asf..?23kj😔gasdf..😅,fwe34 should become this: 😔😅. Then I'd check the length to confirm that it's >=1 and I'd be good to go.

Solution

From what I get from comments, some of this may or may not help -

To validate a string contains 1 or more emoji :

 # ^(?=[\S\s]*(?:\ud83d[\ude00-\ude4f]))

 ^ 
 (?=
      [\S\s]* 
      (?: \ud83d [\ude00-\ude4f] )
 )

To remove only emoji, leaving the rest (global) :

Find: (?:\ud83d[\ude00-\ude4f])*((?:(?!\ud83d[\ude00-\ude4f])[\S\s])+)(?:\ud83d[\ude00-\ude4f])*
Replace: $1

 (?: \ud83d [\ude00-\ude4f] )*
 (                                       # (1 start)
      (?:
           (?! \ud83d [\ude00-\ude4f] )
           [\S\s] 
      )+
 )                                       # (1 end)
 (?: \ud83d [\ude00-\ude4f] )*

To remove everything but emoji (global) :

Find: ((?:\ud83d[\ude00-\ude4f])*)(?:(?!\ud83d[\ude00-\ude4f])[\S\s])+((?:\ud83d[\ude00-\ude4f])*)
Replace: $1$2

 (                                       # (1 start)
      (?: \ud83d [\ude00-\ude4f] )*
 )                                       # (1 end)
 (?:
      (?! \ud83d [\ude00-\ude4f] )
      [\S\s] 
 )+
 (                                       # (2 start)
      (?: \ud83d [\ude00-\ude4f] )*
 )                                       # (2 end)

edit: To use different emoji utf16 ranges do this

Different high surrogates:

(?:
     High_surrogate_A [Low_surrogate_start_A-Low_surrogate_end_A]
  |  High_surrogate_B [Low_surrogate_start_B-Low_surrogate_end_B]
  |  High_surrogate_C [Low_surrogate_start_C-Low_surrogate_end_C]
)

or, same high surrogate, different low surrogate ranges:

(?:
     High_surrogate [Low_surrogate_start1-Low_surrogate_end1Low_surrogate_start2-Low_surrogate_end2]
)

or, mix:

(?:
     High_surrogate_A [Low_surrogate_startA1-Low_surrogate_endA1Low_surrogate_startA2-Low_surrogate_endA2]
  |  High_surrogate_B [Low_surrogate_start_B-Low_surrogate_end_B]
)

Where you see:

(?: \ud83d [\ude00-\ude4f] )*

substitue one of the above in placeholder HERE

HERE*

Where you see:

(?! \ud83d [\ude00-\ude4f] )

substitue one of the above in placeholder HERE

(?! HERE )

Note- you can add a High-surrogate range as well, however all the high surrogates must share the same low-surrogate(s) range.