I am trying to concatenate the second parameter to the first in JS

I’m pretty stuck, It should evaluate to ["present", "pretty", "precede"]

function addTooStart(x, y) {
  let a = [];
  let b = "";
  for (let i in x) {
    a = x.push(y);
    a = x[b]
  }
  return a
}

let abc = addTooStart(["sent", "tty", "cede"], "pre");
console.log(abc)