core-js/internals/same-value.js

// `SameValue` abstract operation
// https://tc39.github.io/ecma262/#sec-samevalue
module.exports = Object.is || function is(x, y) {
  // eslint-disable-next-line no-self-compare
  return x === y ? x !== 0 || 1 / x === 1 / y : x != x && y != y;
};