茉莉如何比较复杂的对象和数组

Question

In jasmine, how does comparison helpers such as expect(a).toEqual() work in the source code? Does it check by ducktyping?

Answer 1

Whenever you are not sure, look into the source code :

(taken from Learn to Read the Source, Luke ).

I won't quote the actual implementation (it's quite big), but here is the underlying util function performing the check.

FYI, it is actually adapted from _.isEqual() and uses stacks to perform deep object and array comparisons.

Note that you can extend the jasmine equality check by adding your custom equality testers .

Answer 2

The short answer

toEqual compares all the properties of both objects and returns true if the corresponding values are equal.

The long answer

You can follow the trail of toEqual in the source code and eventually land here in the eq method which gives the gritty details...(and I quote the source: 'lovingly adapted from isEqual in Underscore ')