code: function is(x, y) {
    let ret = false;
    // SameValue algorithm
    if (x === y) { // Steps 1-5, 7-10
      // Steps 6.b-6.e: +0 != -0
      ret = (x !== 0 || 1 / x === 1 / y);
    } else {
      // Step 6.a: NaN == NaN
      ret = (x !== x && y !== y);
    }
  
    return ret;
  }
docs: inlined Object.is polyfill
  https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
   /* eslint-disable no-self-compare