const lat = "-3340Abcs"
const newLat = lat.replace(/\D/g,"") // getting 3340
//expecting -3340
You can use regex /[^-+\d]/g
const lat = "-3340Abcs";
const newLat = lat.replace(/[^-+\d]/g, "");
console.log(newLat);I assume your expected result is a number. You can use look behind if you want to also remove + and - in the middle of the string:
const lat = "-3340Ab+c-s"
const newLat = lat.replace(/(?<=^)[^+-\d]|(?<!^)\D/g,"");
console.log(newLat);