检查变量是否为空或空字符串的更好方法？

const isEmpty = variable => (variable === null || variable === undefined || variable === '');

const isEmpty = variable => !variable && variable !== 0;

const isEmpty = variable => [null, undefined, ''].includes(variable);

const isEmpty = variable => {
  switch (variable) {
    case null:
    case undefined:
    case '':
      return true;
    default:
      return false;
  }
};

const isEmpty = variable =>
  variable === null ||
  variable === undefined ||
  (typeof variable === 'string' && variable.trim().length === 0) ||
  (Array.isArray(variable) && variable.length === 0);