Regex for validating zero and string

I want a regex in Angular for validating string and decimal

It should allow only numbers up to two decimal places and restrict user to input 0 as first no.

I have created below regex which was working fine, but it is not restricting user to enter
0 as input.

For example Accepted input

2.34
2.05
234.67
77777.87

Not allowed

0
23.5666
24.677
String and special characters


validateBatchSizeForDecimal(event: any) {
    const reg = /^-?d*(.d{0,2})?$/;
    let input = event.target.value + String.fromCharCode(event.charCode);
    if (!reg.test(input)) {
      event.preventDefault();
    }
  }