Is there a splice method for strings?

Question

The Javascript splice only works with arrays. Is there similar method for strings? Or should I create my own custom function?

The substr(),

Answer 1

Louis's spliceSlice method fails when add value is 0 or other falsy values, here is a fix:

function spliceSlice(str, index, count, add) {
  if (index < 0) {
    index = str.length + index;
    if (index < 0) {
      index = 0;
    }
  }
  const hasAdd = typeof add !== 'undefined';
  return str.slice(0, index) + (hasAdd ? add : '') + str.slice(index + count);
}