JS中不使用循环判断对象B的键是否存在于对象A的方法

You can achieve this using JavaScript's array method every() combined with Object.keys()—this abstracts away the loop logic so you don't have to write a manual for/while loop yourself. Here's how it works:

var a = {name1: "hello", game1: "no games", name2: "world"};
var b = {name1:'hello world'};

// Check if all keys in b exist in a
const allKeysExist = Object.keys(b).every(key => a.hasOwnProperty(key));
console.log(allKeysExist); // Output: true

Breakdown: #

1. Object.keys(b) retrieves all enumerable string keys from object b as an array.
2. The every() method tests whether all elements in the array pass the provided function. It stops iterating immediately if it finds a key that fails the test.
3. The arrow function checks if a has the current key using hasOwnProperty(), which ensures we only check direct properties of a (not inherited ones from the prototype chain).

Edge Cases to Consider: #

• If b is an empty object, every() will return true (since there are no keys to fail the check).
• If you need to include non-enumerable keys in your check, replace Object.keys(b) with Object.getOwnPropertyNames(b).
• If your objects use symbol keys, use Reflect.ownKeys(b) instead—it captures both string and symbol keys, regardless of whether they're enumerable.

Example with a failing case (when b has a key not present in a):

var b = {name1:'hello world', name3: 'test'};
const allKeysExist = Object.keys(b).every(key => a.hasOwnProperty(key));
console.log(allKeysExist); // Output: false

内容的提问来源于stack exchange，提问作者Alisha Sharma