Are you stuck on finding a solution on how to check if a value is a number using isnumeric in JavaScript?
Look no further because this article gathered all the needed information just for you! So keep reading!
To learn how to check if a value is a number or not in JavaScript.
Before we dive into the solutions, let’s first understand what data types are.
Data Types in JavaScript
In JavaScript, each value is associated with a particular data type. Knowledge of these data types is vital because they serve as the building blocks for various operations, including numeric evaluations.
Here are some essential data types in JavaScript:
Data Types | Description |
---|---|
Number | This data type includes both integers and decimal numbers or floating-point numbers, like 18 or 3.14. |
String | This type represents a collection of characters enclosed within either single or double quotes. |
Boolean | This type represents true or false values. |
Object | This data type is used to represent intricate and sophisticated data structures. |
Undefined | This refers to a variable that has been created but not given any value yet. |
Null | This indicates that there is no specific object value assigned or present intentionally. |
Symbol | This refers to values that are distinct and immutable values or cannot be changed once created. |
What is isnumeric?
The isNumeric is a function that checks if an expression can be evaluated as a number.
It returns a Boolean value indicating whether the expression is numeric or not.
Here’s the example of isnumeric:
isNumeric(10); // true
isNumeric(0144) //true
isNumeric("3.14"); // true
isNumeric("143-5”); // true
isNumeric( 0xFF) // true
isNumeric(+13) // true
isNumeric("1") // true
isNumeric(Infinity); // false , use isFinite()
isNumeric(NaN); // false , use isNaN()
isNumeric([0]); // false
isNumeric(true); // false
isNumeric("foo"); // false
isNumeric(null); // false
isNumeric(new Date()); // false
isNumeric( Infinity ) // false
isNumeric( undefined ) // false
isNumeric( "" ) // false
isNumeric( {} ) // false
The isNumeric function is accessible in various programming languages, including Python and Visual Basic for Applications.
In Python, the isnumeric() method serves this purpose, returning a True value when all the characters within a string are numeric (0-9), and False otherwise.
It’s worth noting that exponents, such as ² and ¾, are also considered to be numeric values under this evaluation.
Unfortunately, there is no isNumeric function in JavaScript. Luckily, you can use other methods such as isInteger(), typeof(), isNaN(), and more to check if a value is a number in JavaScript.
In simple words, the isNumeric function is not a built-in feature in JavaScript, but it can be easily implemented to check whether a value is numeric.
Different ways to check isnumeric in JavaScript
Here are some examples of how to check if a value is a number in JavaScript:
Solution 1: Using the isInteger() method
For example:
let samplevalue = 1;
console.log(Number.isInteger(samplevalue));✅
Output:
true
Solution 2: Using the typeof() operator
For example:
let samplevalue = 2;
console.log(typeof samplevalue === 'number');
Output:
true
Solution 3: Using the isNaN() global variable
For example:
let samplevalue = 3;
console.log(!isNaN(samplevalue));
Output:
true
Solution 4: Using the parseFloat() function
For example:
let samplevalue = "4";
console.log(parseFloat(samplevalue) == samplevalue);
Output:
true
Solution 5: Using the parseInt() function
For example:
let samplevalue = "5";
console.log(parseInt(samplevalue) == samplevalue);
Output:
true
Solution 6: Using a regular expression
For example:
let samplevalue = "6";
console.log(/^\d+$/.test(samplevalue));
Output:
true
The list of solutions above is just a few ways to check if a value is a number in JavaScript, and you can use any of these methods depending on your needs.
Examples of Numeric Values in JavaScript
For you to have a better understanding, let’s check out some examples of how to determine if a value is numeric in JavaScript:
Example 1: Numeric Value
For example:
let samplenum = 1;
console.log(!isNaN(samplenum));
Here, we have a number 1 stored in a variable called “samplenum.” To check if “num” is a number, we use a function called isNaN(), which stands for “is Not a Number.”
When we apply isNaN() to “num,” it will give us a response. If “num” is a number, the function will return “false,” meaning it is a valid numeric value. So, in this example, the output will be “true” because “num” is a numeric value.
Output:
true
Example 2: Numeric String
For example:
let strNum = "2.14";
console.log(!isNaN(strNum));
Here, we have a variable strNum assigned to the string value “2.14”, which represents a numeric value. By using the isNaN() function, we check if strNum is a numeric value.
As “2.14” can be interpreted as a number, the output will be true.
Output:
true
Example 3: Non-Numeric String
For example:
let nonNumStr = "Itsourcecode";
console.log(!isNaN(nonNumStr));
As you can see, the variable nonNumStr is assigned the string value “Itsourcecode,” which is not a numeric value.
The isNaN() function will return true for non-numeric strings, so the output will be false.
Output:
false
Example 4: Boolean Value
For example:
let samboolValue = true;
console.log(!isNaN(samboolValue));
Here, we have a variable samboolValue assigned to the boolean value true.
Although true and false are represented as 1 and 0 in some contexts, they are not considered numeric values in JavaScript. Therefore, the output will be true.
Output:
true
Example 5: Undefined Value
For example:
let undefinedValue;
console.log(!isNaN(undefinedValue));
Here, we have the variable undefinedValue is not assigned a value, resulting in undefined. Since undefined is not a numeric value, the isNaN() function will return true, and the output will be false.
Output:
false
Example 6: Null Value
For example:
let nullValue = null;
console.log(!isNaN(nullValue));
As you have noticed, the variable nullValue is assigned the value null, which is not a numeric value. Similar to undefined, null is not considered numeric, and the isNaN() function will return true, resulting in an output of false.
Output:
Output: false
Conclusion
In conclusion, this article explains how to check if a value is a number in JavaScript and provides enough solutions using various methods.
While there is no built-in “isNumeric” function in JavaScript, we can utilize other techniques such as “Number.isInteger(),” “typeof(),” “isNaN(),” “parseFloat(),” “parseInt(),” and regular expressions to achieve the desired result.
Using the solutions that this article has already given, you can effectively validate numeric values in your JavaScript code.
We are hoping that this article provides you with enough information that helps you understand the isnumeric in JavaScript.
You can also check out the following article:
Thank you for reading itsourcecoders 😊.