firebase - functions.database.DeltaSnapshot#changed unexpected result -

i using changed() function in functions , result not expected given documentation.

i added few tests following file illustrate issue. https://github.com/firebase/firebase-functions/blob/master/src/providers/database.ts

it('should false when current value has not changed', () => {   populate({ a: { b: 'c' } }, { a: { b: 'c' } });   expect(subject.child('a').changed()).to.be.false; });  it('should false when current value has not changed, child path exists', () => {   populate({ a: { b: 'c' } }, { a: { b: 'c' } });   expect(subject.child('a/b').changed()).to.be.false; });  it('should false when current value has not changed, child path not exist', () => {   populate({ a: { b: 'c' } }, { a: { b: 'c' } });   expect(subject.child('a/d').changed()).to.be.false; }); 

the first 2 tests fail, expected changed() function return false. misunderstand documentation?

refs https://firebase.google.com/docs/reference/functions/functions.database.deltasnapshot#changed

in unit tests of firebase sdk cloud functions, signature of populate populate(data, delta). is, original data , change original data.

when sdk checks changes, seeing if value present in delta payload. in deployed function, hasn't changed explicitly not sent in delta payload.