How to check value in the array is present in the array variable or not? [duplicate]

Question

I wanted to achieve a value in the array is present in the array variable or not.

var a = [1, 2, 3];
if (a === 1) {
    alert("green");
}

So my goal is to check in the variable a holds the value 1 or not.

Answer 1

Use includes:

let a = [1, 2, 3]

if (a.includes(1))
  console.log('exist');
else
  console.log('not exist');

Answer 2

You need to loop through array members and check if any of the members has that value. Here's an example:

var a = [1,2,3];
for(let i = 0; i < a.length; i++){
   if(a[i] == 1){
      alert("green");
   }
}