angular input value just below the input code example

Example 1: preventing +,-,e from input ts

<input(keyup)="_keyUp($event)">

Example 2: preventing letters from being placed in an input ts

validateNumber(event) {
    const keyCode = event.keyCode;

    const excludedKeys = [8, 37, 39, 46];

    if (!((keyCode >= 48 && keyCode <= 57) ||
      (keyCode >= 96 && keyCode <= 105) ||
      (excludedKeys.includes(keyCode)))) {
      event.preventDefault();
    }
  }

Example 3: preventing +,-,e from input ts

_keyUp(event: any) {
    const pattern = /[0-9\+\-\ ]/;
    let inputChar = String.fromCharCode(event.key);

    if (!pattern.test(inputChar)) {
      // invalid character, prevent input
      event.preventDefault();
    }
}