core-js/internals/math-sign.js

// `Math.sign` method implementation
// https://tc39.github.io/ecma262/#sec-math.sign
module.exports = Math.sign || function sign(x) {
  // eslint-disable-next-line no-self-compare
  return (x = +x) == 0 || x != x ? x : x < 0 ? -1 : 1;
};