JSFiddle - React, Tailwind, and code Playground
JavaScript
var regex = /^\s*\S+(\s?\S)*\s*$/;
var cases = [" "," ","foo","foo bar","foo "," foo"," foo "];
for(var i=0,l=cases.length;i<l;i++)
{
if(regex.test(cases[i]))
console.log(cases[i]+' matches');
else
console.log(cases[i]+' doesn\'t match');
}