js check if var is in array code example

Example 1: get if there is a value in an array node js

myArray = Array(/*element1, element2, etc...*/);

// If the array 'myArray' contains the element 'valueWeSearch'
if(myArray.includes(valueWeSearch))
{
 	// Do something
}

Example 2: javascript test if it is an array

// If you want to test if a variable (object) is an instance of 
// an array. You can use the Array.isArray(varName) method
// this method takes one argument, the variable or object you want to test
// and returns true, if the argument is an array 
// or false, if the argument is not an array

if (Array.isArray(object)) {
	// is true
} else {
	// is false
}

Array.isArray([1, 2, 3, 4]); // Returns true
Array.isArray(4); // returns false
// this could be used for flattening an array of arrays

Example 3: check items in array javascript

function checkAllEven(arr) {
  return arr.every(function(x){
	 return	x % 2 === 0
	})
}

//using "every" to check every item in array.