类型错误：使用 jasmine 进行单元测试时未定义不是对象

Question

I'm trying to write a unit test for a function and I'm getting an error. I'm also unsure how to test other parts of the function correctly.

private dictionaryMap (loggedIn, response) {
    const translations = this.convertToArrays(response.data.translations);

    this.configureMomentLocale(language);

    if (!loggedIn) {
        this.cachePublicDictionary(translations);
    }

    // not testing this part
    this.dictionary = new Dictionary({
        translationMap: Object.assign({}, this.getPublicDictionaryFromCache() || {}, translations),
    });

    return this.rx.Observable.of(this.dictionary);
}

And my unit test so far looks like this:

describe('dictionaryMap', () => {

    it('calls configureMomentLocale()', () => {
        const foo = {
            'foo':'bar',
        };
        spyOn(service, 'configureMomentLocale');
        service.dictionaryMap({}, false);
        expect(service.configureMomentLocale).toHaveBeenCalled();
    });

});

And when I run this test I get this error:

TypeError: undefined is not an object (evaluating 'response.data.translationMap')

Do I need to mock response.data.translations or assign the json structure? (translationMap: {'email': 'email', 'forgotPassword': 'Forgot password?'})

Also, I'm not sure how to properly test the other parts of the function, like the if statement or returning the observable. I am new to unit testing.

Answer 1

Your method dictionaryMap accepts 2 parameters - 1st is loggedIn (presumably boolean) and the 2nd one is response . On the first line of that method (before calling configureMomentLocale ) you have a line const translations = this.convertToArrays(response.data.translations); which expects the response variable to have a property named data .

In your test, you have 2 errors on the line service.dictionaryMap({}, false); :

1. You're setting the arguments in reverse order - you should put the boolean argument first and the object one second
2. The object doesn't have a property named data

The line should be corrected to be something similar to service.dictionaryMap(false, { data: {} }); . You might even need to define translations property for data object - it really depends on what this.convertToArrays function does and how it handles undefined values.