Use your regex and list-template from regexr directly in your code.

regexrList.js

function regexrList(captureRegEx, listTemplate, str) {
// map for every match
  const matchesToTemplate = (match) => {
     // replace for every group in match
      return  match.reduce((acc,group,i)=>{
       // 0th index is $n, others follow index number $1,$2
        var key = '\\$' + (i==0 ? 'n' : i)
        var regex = new RegExp(key,'g')
        // example: replace $1 with match[1] which is 'group'
        var replaced = acc.replace(regex,group)
          return replaced
      },listTemplate)
  };

  return Array.from(str.matchAll(captureRegEx), matchesToTemplate).join("");
}

var text = `I love to hate.
I love to hate.
I love to hate.
I love to hate.`

var result =   regexrList(/(love).+(hate)/g, "I $1 to $1.\n",text)

console.log(result)

// >>> "I love to love.
// I love to love.
// I love to love.
// I love to love.
// "