JavaScript developers often encounter the need to validate input for numeric values. IsNumeric() emerges as a versatile function for addressing this challenge.
IsNumeric(): A Comprehensive Validation Tool
IsNumeric() is a robust function designed to handle a wide range of input types, including strings, numbers, and even values of various data structures. Its goal is to determine whether the provided input represents a numeric value.
To ensure clarity and cross-platform compatibility, IsNumeric() leverages JavaScript's built-in functions.
Test Cases and Expected Outcomes
To demonstrate its effectiveness, consider the following test cases with their corresponding expected outcomes:
Test Case | Expected Outcome |
---|---|
'-1' | true |
'-1.5' | true |
'0' | true |
'0.42' | true |
'.42' | true |
'99,999' | false |
'0x89f' | false |
'#abcdef' | false |
'1.2.3' | false |
'' | false |
'blah' | false |
Implementation
The following snippet provides an implementation of the IsNumeric() function:
function isNumeric(n) { return !isNaN(parseFloat(n)) && isFinite(n); }
Considerations and Enhancements
This implementation encompasses all numeric values, including hexadecimal numbers and exponents. However, for applications requiring decimal-only validation, adjustments can be made to the isNumeric() function.
Alternative Implementations
Over the years, various implementations of IsNumeric() have emerged. Here are a few notable alternatives:
jQuery's IsNumeric()
jQuery.isNumeric = function(obj) { var realStringObj = obj && obj.toString(); return !jQuery.isArray(obj) && (realStringObj - parseFloat(realStringObj) + 1) >= 0; }
Angular 4.3's IsNumeric()
export function isNumeric(value: any): boolean { return !isNaN(value - parseFloat(value)); }
These alternative implementations offer different approaches to numeric validation, but all strive to provide a robust and effective solution.
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