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