JSFiddle - React, Tailwind, and code Playground

JavaScript

console.clear();
var arr = ["a","b","c","d"];
for(var i=0;i<arr.length;i++){
	var str = arr[i];
	for(var j=i;j<arr.length;j++){
  	if(i!==j)
    	str+=arr[j];
    console.log(str);
  }
}