How to check array startwith or endwith

index.js

//using Array.prototype

Array.prototype.startWith = function (query){
  if (query === undefined) {
    return this[0]
  }else {
    if (this === []|| this.length === 0){
    return false
  }else {
    return (this[0] === query) ? true:false
  }
  }
}


Array.prototype.endWith = function (query) {
  let end = this.length - 1
  if (query === undefined) {
    return this[end]
  }else {
    if (this === [] || this.length === 0) {
      return false
    }
    else {
      return (this[end] === query) ? true:false
    }
  }
}


//Example usage:
Let car = ["Audi","Toyota","Volvo"]
console.log (car.startWith()) // expected Audi