JavaScript - Array isArray() Method

The JavaScript Array.isArray() method is used to check whether the provided value is an array or not. If it is an array, then this method will return "true", else it returns "false".

Note − This method always returns "false" as result for TypedArray instances.

Syntax

Following is the syntax of JavaScript Array.isArray() method −

array.isArray(object);

Parameters

This method accepts only one parameter. The same is described below −

The parameter "object" is the object to be checked.

Return value

This method returns a boolean value as reuslt. "True" if the given value is an array, else, false.

Examples

Example 1

In the following example, we are using the JavaScript Array.isArray() method to check whether the variable animals is an array or not.

<html>
<body>
   <p id="demo"></p>
   <script>
      const animals = ["Lion", "Cheetah", "Tiger", "Elephant", "Dinosaur"];
      const result = Array.isArray(animals);
      document.getElementById("demo").innerHTML = result;
   </script>
</body>
</html>

Output

The output has returned true because animals is an array.

true

Example 2

Here, we are the variable animals is a string, not an array.

<html>
<body>
   <p id="demo"></p>
   <script>
      const animals = "Lion";
      const result = Array.isArray(animals);
      document.getElementById("demo").innerHTML = result;
   </script>
</body>
</html>

Output

false

Example 3

Following are some other scenarios where the Array.isArray() method will return true −

<html>
<body>
   <p id="demo"></p>
   <script>
      document.write(Array.isArray([]));
      document.write(Array.isArray([100]));
      document.write(Array.isArray(new Array()));
      document.write(Array.isArray(new Array("one", "two", "three", "four")));
      document.write(Array.isArray(new Array(619)));
   </script>
</body>
</html>

Output

truetruetruetruetrue

Example 4

Following are some other scenarios where the Array.isArray() method will return false −

<html>
<body>
   <p id="demo"></p>
   <script>
      document.write(Array.isArray());
      document.write(Array.isArray({}));
      document.write(Array.isArray(null));
      document.write(Array.isArray(undefined));
      document.write(Array.isArray(100));
      document.write(Array.isArray("Hello"));
      document.write(Array.isArray(true));
      document.write(Array.isArray(false));
   </script>
</body>
</html>

Output

falsefalsefalsefalsefalsefalsefalsefalse