如何检查用户输入是否是javascript数组中的元素？

Question

请找到我正在使用的以下代码，并帮助我理解我错在哪里：

let inf = ["love", "clean", "choose"];
let ger = ["like", "have", "smile"];



$('button').click(function(){
let word = document.getElementById("text1").value;

 if (word === inf[]) { 
  alert('this is working')
 };

Answer 1

检查数组是否包含某些内容的正确方法是使用 Array.prototype.includes(); 例如：

let array = ['fruits', 'meat', 'idk'];
if (array.includes('fruits')) { // this if statement is true
   alert('this is working');
}

这样，您检查数组的每个元素是否是您放入方法中的元素。

Answer 2

 let a = [1, 2, 3], b = [], c = 1 /*Check if a variable is an Array*/ console.log(a instanceof Array) console.log(b instanceof Array) console.log(c instanceof Array) /*Check if array includes a certian value and return its index if avalable else returns -1*/ console.log(a.indexOf(2)) console.log(a.indexOf(3)) console.log(a.indexOf(5)) //[-1] Doesn't exist in the array