支付金额输入控制代码

用于商家出示静态收款码，用户扫码自主输入金额进行支付，或在应用内充值、收款等功能限制使用自定义键盘输入金额等业务场景。

live demo

Source code

function inputValidate(val: string): string {
  if (val === '.' || val === '0.') {
    return '0.';
  }
  if (!Number.isNaN(Number(val))) {
    const dotIndex = val.indexOf('.');
    if (dotIndex !== -1) {
      const decimalLength = val.substring(dotIndex + 1).length;
      return decimalLength > 2 ? val.substring(0, dotIndex + 3) : val;
    }
    return val;
  }
  return val;
}

export const moneyKeyboard = {
  input: function (value: string, amount: string): string {
    if (amount.includes('.') && value === '.') {
      return amount;
    }
    if (/^0+$/.test(amount) && value === '.') {
      return '0.';
    }
    const val = amount + value;
    return inputValidate(val);
  },
  backspace: function (amount: string): string {
    return amount.slice(0, -1);
  },
};