13. Refactoring the .move() Method

Refactoring the .move() Method

Question:

Start Quiz:

var carlike = function(obj, loc) {
    obj.loc = loc;
    obj.move = function() {
        this.loc++;
    };
    return obj;
};

var amy = carlike({}, 1);
amy.move();
var ben = carlike({}, 9);
ben.move();
/*
this try catch block is just here because karma is stupid.
seriously, if you run
expect(someVar).to.not.exist
and someVar doesn't exist, it spits out a referenceError
instead of passing the test, which is checking to make sure
it doesn't exist.
*/

try {
    move.toString();
} catch (err) {
    var move = undefined;
}

var containsString = function(string, substring) {
    if (string.search(substring) > -1) {
        return true;
    } else {
        return false;
    }
};

describe("TEST: move should not be a global variable.", function() {
    it("move is not in the global scope: ", function() {
        expect(move).to.not.exist;
    });
});

describe("TEST: move should not use 'this'.", function() {
    it("move does not use 'this': ", function() {
        expect(containsString(carlike.toString(), 'this')).to.be.false;
    });
});


describe("TEST: new carlike objects should be able to move.", function() {
    it("a new carlike object can move: ", function() {
        expect(carlike({},1)).to.have.ownProperty('move');
  });
});

describe("TEST: amy should have moved from 1 to 2.", function() {
  it("\nAmy moved from 1 to 2: ", function() {
    amy.loc.should.be.equal(2);
  });
});

describe("TEST: ben should have moved from 9 to 10.", function() {
  it("\nBen moved from 9 to 10: ", function() {
    ben.loc.should.be.equal(10);
  });
});

User's Answer:

(Note: The answer done by the user is not guaranteed to be correct)

var carlike = function(obj, loc) {
    obj.loc = loc;
    obj.move = function() {
        loc++;
    };
    return obj;
};

var amy = carlike({}, 1);
amy.move();
var ben = carlike({}, 9);
ben.move();
/*
this try catch block is just here because karma is stupid.
seriously, if you run
expect(someVar).to.not.exist
and someVar doesn't exist, it spits out a referenceError
instead of passing the test, which is checking to make sure
it doesn't exist.
*/

try {
    move.toString();
} catch (err) {
    var move = undefined;
}

var containsString = function(string, substring) {
    if (string.search(substring) > -1) {
        return true;
    } else {
        return false;
    }
};

describe("TEST: move should not be a global variable.", function() {
    it("move is not in the global scope: ", function() {
        expect(move).to.not.exist;
    });
});

describe("TEST: move should not use 'this'.", function() {
    it("move does not use 'this': ", function() {
        expect(containsString(carlike.toString(), 'this')).to.be.false;
    });
});


describe("TEST: new carlike objects should be able to move.", function() {
    it("a new carlike object can move: ", function() {
        expect(carlike({},1)).to.have.ownProperty('move');
  });
});

describe("TEST: amy should have moved from 1 to 2.", function() {
  it("\nAmy moved from 1 to 2: ", function() {
    amy.loc.should.be.equal(2);
  });
});

describe("TEST: ben should have moved from 9 to 10.", function() {
  it("\nBen moved from 9 to 10: ", function() {
    ben.loc.should.be.equal(10);
  });
});
Solution:

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