Add JavaScript linting and tests

* Add sample malformed JavaScript files to lint on
* In our tests, copy the `node_modules` directory to make `jshint`
  available, then validate that we're correctly linting the staged JS
  file
* In our pre-commit hook, lint the staged JavaScript files. If either of
  our linting commands fail then exit 1 to abort the commit.

1 files changed, 3 insertions, 0 deletions

diff --git a/t/test.js b/t/test.js
new file mode 100644
index 0000000..d864322
--- /dev/null
+++ b/t/test.js
@@ -0,0 +1,3 @@
+var no_semicolon = 0
+1
+&& 0 && 1;