问角5，我被困在检查输入eventKey

EN

controlValue(event) {

let patt = /[0-9]/g;
let itTrue = patt.test(event.key);
console.log(this.startTime.minute)
if (itTrue || event.keyCode == 8 || (event.keyCode > 33 && event.keyCode < 48)) {
  if (event.code == 'ArrowUp') {
    this.startTime.minute++
    if (this.startTime.minute >= 60) {
      this.startTime.minute = 0;
    }
  } else if (event.code == 'ArrowDown') {
    this.startTime.minute--

    if (this.startTime.minute < 0) {
      this.startTime.minute = 59;
    }
  } else if (itTrue) {
    if ((this.startTime.minute + parseInt(event.key)) < 60) {

      console.log('return 1')
      return true
    }
    console.log('return 2')
    return false;
  } else {
    console.log('return 3')
    return true;
  }
} else {
  console.log('return 4')
  return false;
}

<input placeholder="MM" (keypress)="controlValue($event)" maxlength="2" [(ngModel)]="startTime.minute" class="form-control">