Prevent prefer-lodash-method error on chain() in combination with member import

[david-zacharias]

As described in #186 it seems the plugin marks methods on chain with prefer-lodash-method error when chain is imported as member import { chain } from 'lodash'.

This PR fixes this by checking module imports for chain, registering this as general module, and check if a chain() call refers to the import from lodash.

Unfortunately I was not able to cover this change with a test because it requires to test if chain is an imported member from lodash. Hints how to cover this welcome!

[coveralls]

Pull Request Test Coverage Report for Build 407

• 33 of 33 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 401:	0.0%
Covered Lines:	1864
Relevant Lines:	1864

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💛 - Coveralls

[ganimomer]

Great job and thanks for contributing!
Two comments, though:

• You added the chain if it's imported in an ImportDeclaration. You should add this logic for the other case of VariableDeclarator for cases like const {chain} = require('lodash').
• You can add tests in the LodashContext test file. If you take this test for example, you can see it's very similar to what you'd need to do.

Thanks for getting into the internals and fixing this.

[david-zacharias]

You are welcome, thanks for the testing hints!

I have updated my PR with two more commits:

1. Relates to your feedback and adds tests as well as covering the case of requireing via VariableDeclarator
2. I noticed that isImplicitChainStart returned true for chain()... leading e.g. to wrong removal of .value() by no-double-unwrap when used with --fix. My second commit tries to cover that.

[david-zacharias]

@ganimomer May I ask if you had time to take a look at the updated code? Anything I should change?

[ganimomer]

Sorry for taking long to reply!
This looks good. The only thing missing is adding a test in prefer-lodash-method that the original error doesn't reproduce anymore.

[david-zacharias]

Now I have to say sorry for my late reply. I added a test that (from my perspective) covers the originating problem (failed without changes of this PR, runs green with the changes).