JSFiddle - React, Tailwind, and code Playground

JavaScript

const arr = [1, 2, 3, 4, 5];

for (let i1 = 0; i1 < arr.length; i1++) {
  for (let i2 = i1 + 1; i2 < arr.length; i2++) {
        console.log(arr[i1] + ' ' + arr[i2])
     }
}