Check importPath extension with 'dot'

[dplusic]

Assume that importPath is 'exceljs'.
The path does not have an extension.
But it ends with 'js' and will be handled as having an extension.
This misleads the module.
Fixed that by checking an extension with 'dot'.

[coveralls]

Coverage remained the same at 94.86% when pulling c555ef1 on dplusic:bugfix/extensions into bfdc2bb on benmosher:master.

[ljharb]

LGTM, but would you mind adding a test case that would fail without your change?

[dplusic]

I added the test case.

[coveralls]

Coverage remained the same at 94.86% when pulling 1494cc2 on dplusic:bugfix/extensions into bfdc2bb on benmosher:master.

[ljharb]

Hmm, why are there changes but no diffs in tests/files/internal-modules/package.json and tests/files/node_modules/exceljs/excel.js and tests/files/node_modules/exceljs/package.json?

[dplusic]

tests/files/node_modules/exceljs/excel.js is added for resolving. To resolve importPath, there should be js file. tests/files/node_modules/exceljs/index.js is also possible, but I want to follow the structure of 'exceljs'. The content is empty because it is not executed as same as other test files(e.g. tests/files/node_modules/@org/package/index.js).

tests/files/node_modules/exceljs/package.json is added to reference excel.js. Without this file, resolver finds only index.js. This file is not empty, github just suppressed the diff. You can show the diff by clicking it.

tests/files/internal-modules/package.json is added to simulate Two package.json Structure. With this structure and problem of misjudging extension(the first problem of this issue, that is, without my change) together, resolver reports error message. This makes test fail. This file is empty because only the existence affects the problem. The content does not matter.

[jfmengels]

LGTM, thanks @dplusic!
@ljharb do you still want more changes for this?

[coveralls]

Coverage increased (+0.03%) to 96.212% when pulling 3a03aca on dplusic:bugfix/extensions into 523789f on benmosher:master.

[ljharb]

Took care of the rebase.