How to Implement a Custom Numeric Check Function in Pure JavaScript?
Oct 19, 2024 pm 04:58 PM
Pure JavaScript: Function to Check if a Value is Numeric
In jQuery, the isNumeric() function verifies whether a value represents an integer. While JavaScript does not have a similar built-in function, you can implement your own custom check.
To create a function that mimics isNumeric() in pure JavaScript, follow these steps:
-
Define the isNumeric() Function:
<code class="javascript">function isNumeric(n) {</code> -
Check if the Value is a Number:
Use !isNaN(parseFloat(n)) to determine if the value can be successfully parsed as a floating-point number.
-
Ensure the Value is Finite:
Add && isFinite(n) to verify that the number is finite, excluding Infinity and NaN.
-
Complete the Function Definition:
<code class="javascript"> return !isNaN(parseFloat(n)) && isFinite(n); }</code>
Example Usage:
<code class="javascript">const value = 123; const isNumber = isNumeric(value); // Returns true</code>
Note:
It's important to avoid using parseInt() to check for numeric values. While it may initially appear to work, it can lead to unexpected results and is not a reliable way to determine numeric values in JavaScript.
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