old_contents: // 54: Object - is
  // To do: make all tests pass, leave the assert lines unchanged!
  
  var assert = require("assert");
  
  describe('`Object.is()` determines whether two values are the same', function(){
  
    describe('scalar values', function() {
      it('1 is the same as 1', function() {
        const areSame = Object.is(1, '???');
        assert.equal(areSame, true);
      });
      it('int 1 is different to string "1"', function() {
        const areSame = Object.___(1, '1');
        assert.equal(areSame, false);
      });
      it('strings just have to match', function() {
        const areSame = Object.is('one', 'two');
        assert.equal(areSame, true);
      });
      it('+0 is not the same as -0', function() {
        const areSame = -1;
        assert.equal(Object.is(+0, -0), areSame);
      });
      it('NaN is the same as NaN', function() {
        const number = 0;
        assert.equal(Object.is(NaN, number), true);
      });
    });
  
    describe('coercion, as in `==` and `===`, does NOT apply', function() {
      it('+0 != -0', function() {
        const coerced = +0 === -0;
        const isSame = Object.is(+0, -0);
        assert.equal(isSame, coerced);
      });
      it('empty string and `false` are not the same', function() {
        const emptyString = '';
        const isSame = Object.is(emptyString, false);
        assert.equal(isSame, emptyString == false);
      });
      it('NaN', function() {
        const coerced = NaN == NaN;
        const isSame = Object.is(NaN, NaN);
        assert.equal(isSame, coerced);
      });
      it('NaN 0/0', function() {
        const isSame = Object.ISSSSS(NaN, 0/0);
        assert.equal(isSame, true);
      });
    });
  
    describe('complex values', function() {
      it('`{}` is just not the same as `{}`', function() {
        const areSame = '???';
        assert.equal(Object.is({}, {}), areSame);
      });
      it('Map', function() {
        let map1 = new Map([[1, 'one']]);
        let map2 = new Map([[1, 'one']]);
        const areSame = Object.is(map1, map1);
        assert.equal(areSame, false);
      });
    });
  
  });
  
  
new_contents: // 54: Object - is
  // To do: make all tests pass, leave the assert lines unchanged!
  
  var assert = require("assert");
  
  describe('`Object.is()` determines whether two values are the same', function(){
  
    describe('scalar values', function() {
      it('1 is the same as 1', function() {
        const areSame = Object.is(1, 1);
        assert.equal(areSame, true);
      });
      it('int 1 is different to string "1"', function() {
        const areSame = Object.is(1, '1');
        assert.equal(areSame, false);
      });
      it('strings just have to match', function() {
        const areSame = Object.is('one', 'one');
        assert.equal(areSame, true);
      });
      it('+0 is not the same as -0', function() {
        const areSame = false;
        assert.equal(Object.is(+0, -0), areSame);
      });
      it('NaN is the same as NaN', function() {
        const number = NaN;
        assert.equal(Object.is(NaN, number), true);
      });
    });
  
    describe('coercion, as in `==` and `===`, does NOT apply', function() {
      it('+0 != -0', function() {
        const coerced = +0 === -0;
        const isSame = !Object.is(+0, -0);
        assert.equal(isSame, coerced);
      });
      it('empty string and `false` are not the same', function() {
        const emptyString = '';
        const isSame = !Object.is(emptyString, false);
        assert.equal(isSame, emptyString == false);
      });
      it('NaN', function() {
        const coerced = NaN == NaN;
        const isSame = !Object.is(NaN, NaN);
        assert.equal(isSame, coerced);
      });
      it('NaN 0/0', function() {
        const isSame = Object.is(NaN, 0/0);
        assert.equal(isSame, true);
      });
    });
  
    describe('complex values', function() {
      it('`{}` is just not the same as `{}`', function() {
        const areSame = false;
        assert.equal(Object.is({}, {}), areSame);
      });
      it('Map', function() {
        let map1 = new Map([[1, 'one']]);
        let map2 = new Map([[1, 'one']]);
        const areSame = Object.is(map1, map2);
        assert.equal(areSame, false);
      });
    });
  
  });
  
  
subject: fix 54-object-is.js