Get the index of the first element in an array with value greater than x

var array = [400, 4000, 400, 400, 4000];

var result;

for(var i=0, l=array.length; i<l; i++){
  if(array[i] > 400){
    result = i;
    break;
  }
}

if(typeof result !== 'undefined'){
  console.log('number greater than 400 found at array index: ' + result);
} else {
  console.log('no number greater than 400 found in the given arrry.');
}

var array = [400, 4000, 400, 400, 4000];
var index=array.findIndex(function(number) {
  return number > 400;
});
console.log(index);