JSFiddle - React, Tailwind, and code Playground

JavaScript

text = ',34,23,4,5,634,23,12,5,4,3,1234,23,54,,,,,,,123,43,2,3,4,5,3424,,,,,,,,123,,,1234,,,,,,,45,,,56';
    text = text.replace(/,+/g, ','); //replace two commas with one comma
    text = text.replace(/^\s+|\s+$/g,''); //remove the spaces
    textarray = text.split(","); // change them into array
    textarray = textarray.filter(function(e){ return e.length});
    console.log(textarray);                                        

    
    // Now use a function to make the array unique
    Array.prototype.unique = function(){
       var u = {}, a = [];
       for(var i = 0, l = this.length; i < l; ++i){
          if(this[i] in u)
             continue;
          a.push(this[i]);
          u[this[i]] = 1;
       }
       return a;
    }
    
    textarray = textarray.unique();
    text = textarray.join(','); //combine them back to what you want
    console.log(text);