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This feature is well established and works across many devices and browser versions. Its been available across browsers since September 2015.
The Number.parseFloat() static method parses an argument and returns a floating point number. If a number cannot be parsed from the argument, it returns NaN.
function circumference(r) {
if (Number.isNaN(Number.parseFloat(r))) {
return 0;
}
return parseFloat(r) * 2.0 * Math.PI;
}
console.log(circumference("4.567abcdefgh"));
// Expected output: 28.695307297889173
console.log(circumference("abcdefgh"));
// Expected output: 0
Number.parseFloat(string)
stringThe value to parse, coerced to a string. Leading whitespace in this argument is ignored.
A floating point number parsed from the given string.
Or NaN when the first non-whitespace character cannot be converted to a number.
This method has the same functionality as the global parseFloat() function:
Number.parseFloat === parseFloat; // true
Its purpose is modularization of globals.
See parseFloat() for more detail and examples.
| Specification |
|---|
| ECMAScript 2027 LanguageSpecification # sec-number.parsefloat |
This page was last modified on Jul 10, 2025 by MDN contributors.
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