js中判断json中key

let jsonObject = {
  "name": "John",
  "age": 30,
  "city": "New York"
};

if ('name' in jsonObject) {
  console.log("Key 'name' exists.");
} else {
  console.log("Key 'name' does not exist.");
}

let jsonObject = {
  "name": "John",
  "age": 30,
  "city": "New York"
};

if (jsonObject.hasOwnProperty('name')) {
  console.log("Key 'name' exists.");
} else {
  console.log("Key 'name' does not exist.");
}

let jsonObject = {
  "name": "John",
  "age": 30,
  "city": "New York"
};

if (Object.keys(jsonObject).includes('name')) {
  console.log("Key 'name' exists.");
} else {
  console.log("Key 'name' does not exist.");
}

let jsonObject = {};
Object.prototype.fakeKey = "fakeValue";

if ('fakeKey' in jsonObject) {
  console.log("This will be printed, but 'fakeKey' is not actually in jsonObject.");
}

if (jsonObject.hasOwnProperty('fakeKey')) {
  console.log("This will not be printed, as 'fakeKey' is not in jsonObject.");
}