old_contents: describe('Utils', function() {
  
    describe('functions', function() {
  
      it('utils.isArray()', () => {
        assert.isOk(utils.isArray([]));
        assert.isOk(utils.isArray([1, 2, 3, 4]));
        assert.isOk(utils.isArray([{ "a": "b" }]));
        assert.isNotOk(utils.isArray(undefined));
        assert.isNotOk(utils.isArray(null));
        assert.isNotOk(utils.isArray(false));
        assert.isNotOk(utils.isArray(""));
        assert.isNotOk(utils.isArray(1000));
        assert.isNotOk(utils.isArray(0x0));
        assert.isNotOk(utils.isArray(new Object()));
        assert.isNotOk(utils.isArray({}));
      });
  
      it('utils.isObject()', () => {
        assert.isOk(utils.isObject({}));
        assert.isOk(utils.isObject({ 'a': 'b' }));
        assert.isNotOk(utils.isObject([]));
        assert.isNotOk(utils.isObject([{}]));
        assert.isNotOk(utils.isObject([{}, {}]));
      });
  
      it('utils.getArrayDifferentKeys() - simple array', () => {
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([1]), 1);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([1, 2, 3]), 3);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([1, 2, 2, 2, 3, 3, 3, 4]), 4);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([]), 0);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys(null), 0);
      });
  
      it('utils.getArrayDifferentKeys() - object array', () => {
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{}, {}], 'keyname'), 0);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{ 'key': 1 }, { 'key': 2 }], 'key'), 2);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{ 'key': 1 }, { 'key': 2 }, {}, { 'anotherkey': 1 }], 'key'), 2);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{ 'key': 1 }, { 'key': 1 }], 'key'), 1);
      });
  
      it('utils.sortBy()  - sort array', () => {
        var array, expectedResult, result;
        array = [{ x: 1 }, { x: 2 }];
        expectedResult = [{ x: 1 }, { x: 2 }];
        result = utils.sortBy(array, { prop: 'x', desc: false });
        assert.deepEqual(expectedResult, result);
  
        array = [{ x: 1 }, { x: 2 }];
        expectedResult = [{ x: 2 }, { x: 1 }];
        result = utils.sortBy(array, { prop: 'x', desc: true });
        assert.deepEqual(expectedResult, result);
  
        array = [];
        expectedResult = [];
        result = utils.sortBy(array, { prop: 'x', desc: true });
        assert.deepEqual(expectedResult, result);
      });
  
    });
  });
new_contents: describe('Utils', () => {
  
    describe('functions', () => {
  
      it('utils.isArray()', () => {
        assert.isOk(utils.isArray([]));
        assert.isOk(utils.isArray([1, 2, 3, 4]));
        assert.isOk(utils.isArray([{ 'a': 'b' }]));
        assert.isNotOk(utils.isArray(null));
        assert.isNotOk(utils.isArray(false));
        assert.isNotOk(utils.isArray(''));
        assert.isNotOk(utils.isArray(1000));
        assert.isNotOk(utils.isArray(0x0));
        assert.isNotOk(utils.isArray(new Object()));
        assert.isNotOk(utils.isArray({}));
      });
  
      it('utils.isObject()', () => {
        assert.isOk(utils.isObject({}));
        assert.isOk(utils.isObject({ 'a': 'b' }));
        assert.isNotOk(utils.isObject([]));
        assert.isNotOk(utils.isObject([{}]));
        assert.isNotOk(utils.isObject([{}, {}]));
      });
  
      it('utils.getArrayDifferentKeys() - simple array', () => {
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([1]), 1);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([1, 2, 3]), 3);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([1, 2, 2, 2, 3, 3, 3, 4]), 4);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([]), 0);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys(null), 0);
      });
  
      it('utils.getArrayDifferentKeys() - object array', () => {
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{}, {}], 'keyname'), 0);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{ 'key': 1 }, { 'key': 2 }], 'key'), 2);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{ 'key': 1 }, { 'key': 2 }, {}, { 'anotherkey': 1 }], 'key'), 2);
        assert.strictEqual(utils.getNumberOfDifferentArrayKeys([{ 'key': 1 }, { 'key': 1 }], 'key'), 1);
      });
  
      it('utils.sortBy()  - sort array', () => {
        var array, expectedResult, result;
        array = [{ x: 1 }, { x: 2 }];
        expectedResult = [{ x: 1 }, { x: 2 }];
        result = utils.sortBy(array, { prop: 'x', desc: false });
        assert.deepEqual(expectedResult, result);
  
        array = [{ x: 1 }, { x: 2 }];
        expectedResult = [{ x: 2 }, { x: 1 }];
        result = utils.sortBy(array, { prop: 'x', desc: true });
        assert.deepEqual(expectedResult, result);
  
        array = [];
        expectedResult = [];
        result = utils.sortBy(array, { prop: 'x', desc: true });
        assert.deepEqual(expectedResult, result);
      });
  
    });
  });
subject: Improve code style