js从数组中找到想要的对象

//定义方法
Array.prototype.findItem = function (obj) {for (let i = 0; i < this.length; i++) {let item = this[i];if (String(item[obj.key]) === String(obj.val)) {return item}}return null;
};let arr = [{id: 1, name: '张三'},{id: 2, name: '李四'},{id: 3, name: '王五'}
];//使用
console.log(arr.findItem({key: 'id', val: 1}));         //打印结果 {id: 1, name: '张三'}
console.log(arr.findItem({key: 'name', val: '王五'}));  //打印结果 { id: 3, name: '王五' }
console.log(arr.findItem({key: 'id', val: 0}));         //打印结果 null