i have a question about splitting and resplacing substrings based on an array of starts and ends

i have this string saidogAngry Kappa saidogAngry saidogAngry ResidentSleeper ResidentSleeper

i need to replaces with “rep” parts of this string based on an array of this kind:

const eleArray = [
{
    "start": "0",
    "end": "10",
    "rep": "63f5ce1593c142a09d714b34e1938990"
},
{
    "start": "12",
    "end": "16",
    "rep": "25"
},
{
    "start": "18",
    "end": "28",
    "rep": "63f5ce1593c142a09d714b34e1938990"
},
{
    "start": "30",
    "end": "40",
    "rep": "63f5ce1593c142a09d714b34e1938990"
},
{
    "start": "42",
    "end": "56",
    "rep": "245"
},
{
    "start": "58",
    "end": "72",
    "rep": "245"
}
]

the problem is that after the first replace all other index are altered.

my initial idea was with split it in single sections and than remove/replace them

const msgArray = [];
let lastIndex = 0;
eleArray.forEach(ele => {
  msgArray.push(message.slice(Number(lastIndex), Number(ele.start)));
  // msgArray.push(message.slice(Number(ele.start), Number(ele.end+1)));
  msgArray.push(ele.rep);
  lastIndex = Number(ele.end)+1;
});
console.log(msgArray.join('');

there is a simplier way or a more optimized way? i need to have the best best performance out of it because i’m doing a text stream with a big quantity of messages.