Function numberAttribute

packages/core/src/util/coercion.ts:41–47

(value: unknown, fallbackValue = NaN)

 * @see [Built-in transformations](guide/components/inputs#built-in-transformations)
 */
export function numberAttribute(value: unknown, fallbackValue = NaN): number {
  // parseFloat(value) handles most of the cases we're interested in (it treats null, empty string,
  // and other non-number values as NaN, where Number just uses 0) but it considers the string
  // '123hello' to be a valid number. Therefore we also check if Number(value) is NaN.
  const isNumberValue = !isNaN(parseFloat(value as any)) && !isNaN(Number(value));
  return isNumberValue ? Number(value) : fallbackValue;
}