This is a challenge.
Implement a keypad utility class, with the following methods:
- add a digit to the keypad
- add two zeros to the keypad
- remove a digit to the keypad
- convert keypad to a string
The keypad constructor takes the max number of integer digits and the number of decimal places.
The keypad is immutable.
const Keypad = require('keypad-lib').Keypad;
// import { Keypad } from 'keypad-lib';
let d = new Keypad(7,2);
console.log(d.toString());
// outputs "0.00"
d = d.addDigit(1)
.addDigit(2)
.addDigit(3)
.addDigit(4)
.addDigit(5)
.addDigit(6)
.addDigit(7)
.addDigit(8)
.addDigit(9)
.addDigit(0);
console.log(d.toString());
// outputs "1234567.89"