js 判断是否正则表达式

function isRegExp(value) {
  return value instanceof RegExp;
}

console.log(isRegExp(/abc/)); // true
console.log(isRegExp('abc')); // false

function isRegExp(value) {
  return typeof value === 'object' && value !== null && typeof value.source === 'string';
}

console.log(isRegExp(/abc/)); // true
console.log(isRegExp('abc')); // false

function isRegExp(value) {
  return Object.prototype.toString.call(value) === '[object RegExp]';
}

console.log(isRegExp(/abc/)); // true
console.log(isRegExp('abc')); // false

function checkIfRegExp(value) {
  if (isRegExp(value)) {
    console.log('The provided value is a RegExp.');
  } else {
    console.log('The provided value is NOT a RegExp.');
  }
}

checkIfRegExp(/abc/); // 输出: The provided value is a RegExp.
checkIfRegExp('abc'); // 输出: The provided value is NOT a RegExp.
checkIfRegExp({ source: 'abc' }); // 输出: The provided value is NOT a RegExp.