JavaScript: Get the data type

Last update on May 30 2022 10:01:29 (UTC/GMT +8 hours)

JavaScript Function: Exercise-9 with Solution

Write a JavaScript function which accepts an argument and returns the type.

Note : There are six possible values that typeof returns: object, boolean, function, number, string, and undefined.

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Detect JavaScript Data Types</title>
</head>
<body>
  
</body>
</html>

JavaScript Code:

function detect_data_type(value)
{
var dtypes = [Function, RegExp, Number, String, Boolean, Object], x, len;
    
if (typeof value === "object" || typeof value === "function") 
    {
     for (x = 0, len = dtypes.length; x < len; x++) 
     {
            if (value instanceof dtypes[x])
            {
                return dtypes[x];
            }
      }
    }
    
    return typeof value;
}
console.log(detect_data_type(12));
console.log(detect_data_type('w3resource'));
console.log(detect_data_type(false));

Sample Output:

number
string
boolean

Flowchart:

Live Demo:

See the Pen JavaScript -Check a number is prime or not-function-ex- 8 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript function which returns the n rows by n columns identity matrix.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Ref: https://bit.ly/2BXbp04