How to check object is an array in JavaScript ?
Method 1: Using Array.isArray() function.
The Array.isArray() function determines whether the value passed to this function is an array or not. This function returns true if the argument passed is array else it returns false.
Syntax:
Array.isArray(obj)
Parameter:
- obj is any valid object in JavaScript like map, list, array, string, etc.
Return Value: It returns Boolean value true if the object passed is an array or false if the object passed is not an array.
Example 1: This example uses Array.isArray() function to check the object is array or not.
html
<p> Click on button to check for array</p> <button onclick="myFunction()"> Try it</button> <p id="GFG"></p> <script> function myFunction() { var countries = ["India", "USA", "Canada"]; var x = document.getElementById("GFG"); x.innerHTML = Array.isArray(countries); }</script> |
Output:
How to check object is an array in JavaScript?
Example 2: This example uses Array.isArray() function to check the object is array or not.
HTML
<p> Click on button to check for array</p> <button onclick="myFunction()"> Try it</button> <p id="GFG"></p> <script> function myFunction() { // It returns false as the object passed is // String not an array document.write(Array.isArray( 'hello GeeksForGeeks')); }</script> |
Output:
How to check object is an array in JavaScript?
Method 2: Using typeof operator.
In JavaScript, the typeof operator returns the data type of its operand in the form of a string where an operand can be any object, function or variable. However, the problem with this is that it isn’t applicable for determining array.
Syntax:
typeof operand or typeof(operand)
Example:
html
<!DOCTYPE html><html> <head> <title> check object is an array </title></head> <body> <p id="GFG"></p> <script> document.getElementById("GFG").innerHTML = typeof "Geeks" + "<br>" + typeof [1, 2, 3, 4] + "<br>" + typeof {name:'Kartik', age:20} + "<br>" + typeof new Date() + "<br>" + typeof function () {} + "<br>" + typeof job + "<br>" + typeof null; </script></body> </html> |
Output:
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