function findElement(arr, func) {
  let i,isPass=func;
  while(arr.length){//骚气，自我夸奖part1
    i=arr.shift()//骚气，自我夸奖part2
    if(isPass(i))
      return i
  }
}
findElement([1, 2, 3, 4], num => num % 2 === 0);

function findElement(arr, isPass, i) {//骚气，自我夸奖part3
  while(arr.length){
    i=arr.shift()
    if(isPass(i))
      return i
  }
}
findElement([1, 2, 3, 4], num => num % 2 === 0);