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Number.parseFloat() - JavaScript | MDN
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Number.parseFloat()

Baseline Widely available

This feature is well established and works across many devices and browser versions. Its been available across browsers since 2015 9.

Number.parseFloat() . NaN .

In this article

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

js
Number.parseFloat(string);

string

. ToString . .

.

NaN .

Number.parseFloat vs parseFloat

Number.parseFloat() parseFloat() .

js
Number.parseFloat === parseFloat; // true

Number.parseFloat() ECMAScript 2015 . parseFloat() .

Specification
ECMAScript 2027 LanguageSpecification
# sec-number.parsefloat

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