Probably all tests, the `src` folder containing the core NodeJS code is at https://github.com/nodejs/node/tree/master/src. Also keep in mind it builds on top of V8, which is mostly C++: https://github.com/v8/v8.
$ cloc . --exclude-dir test
16921 text files.
14173 unique files.
7043 files ignored.
github.com/AlDanial/cloc v 1.88 T=35.06 s (354.1 files/s, 160714.9 lines/s)
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Language files blank comment code
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Perl 315 23880 21499 1180347
C++ 1673 139959 140151 962404
Assembly 351 49707 9182 583298
JavaScript 3935 82192 107644 461467
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SUM: 12414 534479 586681 4513827
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