> I (or anyone in the future that will ever touch the code) must learn JS. OK. Now they must also learn framework X.
Well you can forget the parts of JS covered by the framework. I don't really care about the native Array.map or whatever functions, because they won't always behave as I expect, while the lodash (or equivalent) will. I can't recall off the top of my head how to use XMLHttpRequest. But I don't need to and haven't needed to in a while, because every project I've worked on uses jQuery or another framework which provided better ajax methods.
Well you can forget the parts of JS covered by the framework. I don't really care about the native Array.map or whatever functions, because they won't always behave as I expect, while the lodash (or equivalent) will. I can't recall off the top of my head how to use XMLHttpRequest. But I don't need to and haven't needed to in a while, because every project I've worked on uses jQuery or another framework which provided better ajax methods.