[[CHORE]] Relocate development dependencies

The `phantom` and `phantomjs-prebuilt` modules cannot be installed in
legacy versions of Node.js because during their installation procedure,
they import code which uses ES2015 language features. When executed in
legacy versions of Node.js, this causes a syntax error, interrupting
installation and making it impossible to execute the project's tests.

A previous commit [1] addressed this issue by marking the dependencies
as "optional." This allowed the installation procedure to fail, and
because the packages are only necessary in the latest release of
Node.js, the relevant tests could execute as expected.

Unfortunately, this modification had an unintended effect on consumers
of JSHint: it forced them to also install the aforementioned packages.
Because these packages are only necessary when contributing to JSHint
(not when using it) and because they include large binary assets, this
had a non-trivial impact on the time and disk space required to install
JSHint.

Revert the previous change, marking the packages as "dev dependencies"
once again. Ensure that the project's tests can continue to execute in
legacy versions of Node.js by introducing a script that removes the
offending packages prior to installation on those platforms.

[1] 2f6ac13

.travis.yml

@@ -1,5 +1,12 @@
 language: node_js
 after_success: npm run coverage && cat ./coverage/lcov.info | coveralls
+before_install:
+  # These packages cannot be installed in legacy versions of Node.js. Because
+  # they are only needed to verify correctness in a browser-like environment,
+  # they can be removed (and the tests skipped) without effecting coverage.
+  - if [[ $(node --version) != v6* ]] ; then
+      node scripts/remove-dev-dependencies.js phantom phantomjs-prebuilt;
+    fi
 script:
   - npm run pretest
   - npm run test-node

appveyor.yml

@@ -12,6 +12,10 @@ environment:
 install:
   - ps: Install-Product node $env:nodejs_version
   - git submodule update --init --recursive
+  # These packages cannot be installed in legacy versions of Node.js. Because
+  # they are only needed to verify correctness in a browser-like environment,
+  # they can be removed (and the tests skipped) without effecting coverage.
+  - if NOT "%nodejs_version%" == "6" node scripts/remove-dev-dependencies.js phantom phantomjs-prebuilt
   - npm install
 
 build: off

package.json

@@ -59,16 +59,14 @@
     "jscs": "1.11.x",
     "mock-stdin": "0.3.x",
     "nodeunit": "0.9.x",
+    "phantom": "~4.0.1",
+    "phantomjs-prebuilt": "~2.1.7",
     "regenerate": "1.2.x",
     "results-interpreter": "~1.0.0",
     "sinon": "1.12.x",
     "test262-stream": "~1.1.0",
     "unicode-11.0.0": "0.7.x"
   },
-  "optionalDependencies": {
-    "phantom": "~4.0.1",
-    "phantomjs-prebuilt": "~2.1.7"
-  },
   "license": "(MIT AND JSON)",
   "preferGlobal": true,
   "files": [

scripts/remove-dev-dependencies.js

@@ -0,0 +1,37 @@
+"use strict"
+/**
+ * Some of this project's development dependencies cannot be successfully
+ * installed in legacy versions of Node.js. This module removes development
+ * dependencies from the project's npm package manifest so that the `npm`
+ * utility does not attempt to install them in a subsequent execution of `npm
+ * install. Although the `npm` utility offers a "remove" command, that command
+ * can remove only one package per invocation and triggers installation of all
+ * other packages. This script allows mutliple packages to be removed prior to
+ * installation.
+ */
+
+var path = require("path");
+var fs = require("fs");
+var manifestLocation = path.join(__dirname, "..", "package.json");
+var manifest = require(manifestLocation);
+var packageNames = process.argv.slice(2);
+var newContents;
+
+packageNames.forEach(function(packageName) {
+  if (!manifest.devDependencies[packageName]) {
+    throw new Error("Could not locate development dependency named \"" + packageName + "\"");
+  }
+
+  delete manifest.devDependencies[packageName];
+});
+
+newContents = JSON.stringify(manifest, null, 2);
+
+fs.writeFile(manifestLocation, newContents, function(err) {
+  if (err) {
+    throw new Error(err);
+  }
+
+  console.log("Successfully removed packages. New contents:");
+  console.log(newContents.replace(/(^|\n)/g, "$1> "));
+});