JSFiddle - React, Tailwind, and code Playground

JavaScript

myArray = ["ABAB", "ABAB", "ABAB", "CDCD", "EFEF", "EFEF"];

container={};

 for(var i=0; i < myArray.length;i++){
        var el=myArray[i];
        if( el in container){
            container[el].push(el);
        }
        else{
            container[el]=[];
            container[el].push(el);
        }


    }
    console.log(container);