Using jshint with Travis CI

I thought I’d give Travis CI a try. It’s a tool that hooks into GitHub and runs automated tests on your code every time you push a commit. I found a straightforward tutorial that basically said I’d need 2 files in addition to my existing code:

  1. .travis.yml
  2. package.json

Simple! I configured Travis CI to run JSHint (a Javascript code linter, similar to JSLint) on the Javascript files in my Simple Steganography project.

I pushed a commit and discovered my files did not pass JSHint. However, I thought they should be. My files were previously configured for JSLint, and JSHint can read JSLint directives. At the top of my Javascript files I had the directives:

/*jslint
bitwise, browser
*/

These indicate that bitwise operators should be allowed, and to assume the code is running in a web browser.

JSHint (via Travis-CI) reported the following errors:

js/decode.js: line 3, col 1, Bad option value.
js/decode.js: line 3, col 1, Bad option value.

The JSHint docs on inline configuration indicate that the formatting should be option: Boolean, so I reformatted the configuration directives:

/*jslint
bitwise: false,
browser: true
*/

JSHint (via Travis-CI) reported several errors regarding bitwise operators:

js/encode.js: line 179, col 37, Unexpected use of '&'.
js/encode.js: line 179, col 42, Unexpected use of '^'.
js/encode.js: line 179, col 53, Unexpected use of '&'.
js/encode.js: line 180, col 51, Unexpected use of '|'.
js/encode.js: line 182, col 51, Unexpected use of '&'.

I changed the JSHint configuration directives to:

/*jslint
bitwise: true,
browser: true
*/

This worked, and my JSHint tests passed! I added a build status image to my GitHub repo:
GitHub build status for Simple Steganography project

The page describing the JSHint Options definitely leads me to believe that enabling the bitwise option would enforce bitwise errors. This is the opposite of the behavior I’m seeing. The problem is either with the documentation, the behavior, or my reading comprehension! I opened a GitHub issue on the JSHint project describing what I experienced.

One thought on “Using jshint with Travis CI”

  1. The issue is that jslint and jshint use the bitwise option in contradictory ways. JSHint correctly interprets the option, but that interpretation differs depending on whether jslint or jshint is specified.

    From the jslint help docs:

    bitwise: true if bitwise operators should be allowed. The bitwise operators are rarely used in JavaScript programs, so it is usually more likely that & is a mistyping of && than that it indicates a bitwise and. JSLint will give warnings on the bitwise operators unless this option is selected.

    From the jshint options documentation:

    bitwise: This option prohibits the use of bitwise operators such as ^ (XOR), | (OR) and others. Bitwise operators are very rare in JavaScript programs and quite often & is simply a mistyped &&.

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