> For the complete documentation index, see [llms.txt](https://hannahpun.gitbook.io/leetcode-note/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hannahpun.gitbook.io/leetcode-note/tools/object-method.md). # Object Method v
Methodexample
Object.hasOwn(obj, key) 取代舊的 Object.hasOwnProperty

let b = ["a", "b", ,"d"]
for (let i = 0; i< b.length; i++){

if (Object.hasOwn(b, i)) {

console.log(b[i])

}

}; // 'a'. 'b' 'd'

Object.prototype.toString.call()判斷是哪種型別好用
Object.prototype.toString.call([1,2]) // "[object Array]"
Object.prototype.toString.call(1); // '[object Number]'
Object.prototype.toString.call('string') // '[object String]'
Object.prototype.toString.call({a: [1,2]}) // '[object Object]'
Object.keys(obj)Array 也是 Object 一種所以也可以Object.keys({a: 1, b: 2}) // [a, b]
Object.keys(["a", "b"]) // [0, 1]
Object.values(obj)Object.values({a: 1, b: 2}) // [1, 2] Object.values(["a", "b"]) // [1, 2]
Object.entries(obj)Object.entries({a: 1, b: 2}) // [[a, 1], [b,2]] Object.entries(["a", "b"]) // [[0,a], [1,b]]
Object.fromEntries(arr)跟 Object.entries(obj) 相反Object.fromEntries([[0,'a'], [1,'b']]) // [{0: 'a', 1: 'b'}