Usage of nullish coalescing syntax errors when running in some browser versions

[jfernandezgersol]

Hi,

I updated the library to a newer version in my project (3.0.0) and I was getting some strange errors running tests with Karma and Jasmine:

Chrome 68.0.3419.0 (Windows 10) ERROR An error was thrown in afterAll Uncaught SyntaxError: Unexpected token ? Chrome 68.0.3419.0 (Windows 10) ERROR An error was thrown in afterAll Uncaught SyntaxError: Unexpected token ? SyntaxError: Unexpected token ? Chrome 68.0.3419.0 (Windows 10): Executed 0 of 0 ERROR (0 secs / 0 secs) Chrome 68.0.3419.0 (Windows 10) ERROR An error was thrown in afterAll Uncaught SyntaxError: Unexpected token ? SyntaxError: Unexpected token ?

After some research, I detected that the problem was related with the apollo-angular library, concretely with the following line:

options.useMutationLoading ?? this.useMutationLoading

referenced in:

apollo-angular/packages/apollo-angular/src/apollo.ts

Line 73 in dee1c98

options.useMutationLoading ?? this.useMutationLoading,

I am using Chrome Headles v68.0.3419.0 to run the tests and the nullish coalescing operator is not recognized.

After some further research, I realized that the support of this operator is relatively new in Safari for iOS too (from iOS version 13.3).

https://caniuse.com/mdn-javascript_operators_nullish_coalescing

I suppose, that this line can be changed to not use ?? and then the browser compatibility won't be reduced.

Thanks in advance!