Best way to find if an item is in a JavaScript array? [duplicate]

問題：

This question already has answers here : 這個問題在這裏已經有了答案：

How do I check if an array includes a value in JavaScript? 如何檢查數組是否包含 JavaScript 中的值？ (55 answers) (55 個回答)

Closed 4 years ago . 4年前關閉。

What is the best way to find if an object is in an array?查找對象是否在數組中的最佳方法是什麼？

This is the best way I know:這是我所知道的最好的方法：

function include(arr, obj) { for (var i = 0; i < arr.length; i++) { if (arr[i] == obj) return true; } } console.log(include([1, 2, 3, 4], 3)); // true console.log(include([1, 2, 3, 4], 6)); // undefined

---

解決方案：

參考一： https://en.stackoom.com/question/bQ7
參考二： https://stackoom.com/question/bQ7