Is There an Alternative to jQuery\'s isNumeric() in Pure JavaScript?

Determining Numeric Values in Pure JavaScript: An Alternative to jQuery's isNumeric()

The jQuery library provides a convenient function, isNumeric(), for verifying whether a value represents a number. However, for situations where jQuery is unavailable, it's essential to know if there are alternatives in pure JavaScript.

The Challenge of Testing for Numbers

In JavaScript, determining the type of a value is not always straightforward. Using the typeof operator, one might intuitively assume that verifying if a value is a number can be achieved simply by checking if its typeof is "number." However, this approach has limitations.

Crafting Your Own isNumeric() Function

Since JavaScript lacks a built-in isNumeric() function, a custom implementation becomes necessary.

Implementation:

<code class="javascript">function isNumeric(n) {
  return !isNaN(parseFloat(n)) && isFinite(n);
}</code>

Explanation:

• parseFloat(): Attempts to convert the input to a floating-point number. If successful, it returns a number value, otherwise it returns NaN (Not a Number).
• isNaN(): Checks if the result of parseFloat() is NaN, indicating that the input is not numeric.
• isFinite(): Verifies that the input is a finite number (not Infinity or -Infinity).

Usage:

<code class="javascript">const value = 10;
console.log(isNumeric(value)); // true</code>

Important Note

It's worth emphasizing that parseInt() should not be employed for numeric validation. parseInt() coerces strings to integers based on their radix (usually 10), which can yield incorrect results for non-integer inputs.

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