@rbxts/jsnatives


parseFloat

Parses a string and returns a floating point number.

Signature

function parseFloat(value: unknown): number

Description

The Number.parseFloat() method parses a string argument and returns a floating point number. It works the same way as the global parseFloat() function.

If the first character cannot be converted to a number, NaN is returned.

Parameters

Return value

Examples

Basic Usage

// Parsing simple number strings
Number.parseFloat("3.14");             // 3.14
Number.parseFloat("42");               // 42 (integer is also a float)
Number.parseFloat("    3.14   ");      // 3.14 (whitespace is ignored)


// Parsing strings with units
Number.parseFloat("3.14meters");       // 3.14 (stops at non-numeric character)
Number.parseFloat("10px");             // 10 (stops at 'p')


// Invalid first characters
Number.parseFloat("abc");              // NaN
Number.parseFloat("$100");             // NaN ($ is not a number)
Number.parseFloat("width: 100px");     // NaN

Handling Different Numeric Formats

// Scientific notation
Number.parseFloat("1.234e+5");         // 123400
Number.parseFloat("5e-3");             // 0.005


// Leading characters
Number.parseFloat("+3.14");            // 3.14
Number.parseFloat("-3.14");            // -3.14


// Decimal point
Number.parseFloat("3,14");             // 3 (stops at comma in many locales)
Number.parseFloat(".5");               // 0.5

Processing User Input

// Extract numeric value from user input
function extractNumericValue(input: string): number {
  const result = Number.parseFloat(input);


  if (Number.isNaN(result)) {
    console.warn(`Could not parse numeric value from "${input}"`);
    return 0; // Default value
  }


  return result;
}


// Usage
extractNumericValue("3.14");           // 3.14
extractNumericValue("price: 19.99");   // 0 (with warning)
extractNumericValue("$29.99");         // 0 (with warning)