Make boot script load settings from correct config tags (#243)

An inconsistency crept in where the annotator code reads settings from
JSON script tags with a 'js-hypothesis-config' class name but the sidebar app
reads settings from JSON script tags with a 'js-hypothesis-settings'
class name. The boot script ended up using 'js-hypothesis-settings'
which is the default class name specified in `settings.js`.

We should use the same name everywhere, which needs to be
'js-hypothesis-config' since that is used by the public documentation
[1].

This commit changes the default class to `js-hypothesis-config` and
removes the ability to specify alternative class names when calling
`settings()`.

The extension and service will need to be updated to use the new class
name.

[1] See docs/config.md

src/annotator/config.js

@@ -18,7 +18,7 @@ function config(window_) {
 
   // Parse config from `<script class="js-hypothesis-config">` tags
   try {
-    Object.assign(options, settings(window_.document, 'js-hypothesis-config'));
+    Object.assign(options, settings(window_.document));
   } catch (err) {
     console.warn('Could not parse settings from js-hypothesis-config tags',
       err);

src/shared/settings.js

@@ -15,20 +15,16 @@ function assign(dest, src) {
  * Return application configuration information from the host page.
  *
  * Exposes shared application settings, read from script tags with the
- * class `settingsClass` which contain JSON content.
+ * class `js-hypothesis-config` which contain JSON content.
  *
  * If there are multiple such tags, the configuration from each is merged.
  *
  * @param {Document|Element} document - The root element to search for
  *                                      <script> settings tags.
- * @param {string} settingsClass - The class name to match on <script> tags.
  */
-function settings(document, settingsClass) {
-  if (!settingsClass) {
-    settingsClass = 'js-hypothesis-settings';
-  }
+function settings(document) {
   var settingsElements =
-    document.querySelectorAll('script.' + settingsClass);
+    document.querySelectorAll('script.js-hypothesis-config');
 
   var config = {};
   for (var i=0; i < settingsElements.length; i++) {

src/shared/test/settings-test.js

@@ -2,11 +2,11 @@
 
 var settings = require('../settings');
 
-function createJSONScriptTag(obj, className) {
+function createConfigElement(obj) {
   var el = document.createElement('script');
   el.type = 'application/json';
   el.textContent = JSON.stringify(obj);
-  el.classList.add(className);
+  el.classList.add('js-hypothesis-config');
   el.classList.add('js-settings-test');
   return el;
 }
@@ -21,22 +21,14 @@ function removeJSONScriptTags() {
 describe('settings', function () {
   afterEach(removeJSONScriptTags);
 
-  it('reads config from .js-hypothesis-settings <script> tags', function () {
-    document.body.appendChild(createJSONScriptTag({key:'value'},
-      'js-hypothesis-settings'));
+  it('reads config from .js-hypothesis-config <script> tags', function () {
+    document.body.appendChild(createConfigElement({key:'value'}));
     assert.deepEqual(settings(document), {key:'value'});
   });
 
-  it('reads config from <script> tags with the specified class name', function () {
-    document.body.appendChild(createJSONScriptTag({foo:'bar'},
-      'js-custom-settings'));
-    assert.deepEqual(settings(document), {});
-    assert.deepEqual(settings(document, 'js-custom-settings'), {foo:'bar'});
-  });
-
   it('merges settings from all config <script> tags', function () {
-    document.body.appendChild(createJSONScriptTag({a: 1}, 'settings'));
-    document.body.appendChild(createJSONScriptTag({b: 2}, 'settings'));
-    assert.deepEqual(settings(document, 'settings'), {a: 1, b: 2});
+    document.body.appendChild(createConfigElement({a: 1}));
+    document.body.appendChild(createConfigElement({b: 2}));
+    assert.deepEqual(settings(document), {a: 1, b: 2});
   });
 });

src/sidebar/app.js

@@ -5,7 +5,9 @@ require('../shared/polyfills');
 
 var raven;
 
+// Read settings rendered into sidebar app HTML by service/extension.
 var settings = require('../shared/settings')(document);
+
 if (settings.raven) {
   // Initialize Raven. This is required at the top of this file
   // so that it happens early in the app's startup flow