Tagged Template Literal

const name = "Hemant";
const age = 30;


function highlight(strings, ...values){
  let str = '';

  strings.forEach((s, i)=> {
    str += `${s} <span class="hl">${values[i] || ''}</span>`;
  });

  return str;
}

var str = highlight`my name is ${name} my age is ${age}`;
console.log(str)