core/polyfills/number.js

/**
 * @private
 * Number.isNaN
 * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN
 */
export function isNaN(value) {
  /* eslint-disable no-self-compare  */
  return value !== value;
  /* eslint-enable no-self-compare  */
}
Number.isNaN = Number.isNaN || isNaN;