Remove options.defaultValue from hostPageSetting

- defaultValue is now handled inside of getConfig so this code is unused.

- hostPageSetting now returns undefined, rather than null, if a value is not found in the config. The undefined value will trigger the defaultValue to take effect in getConfig if a defaultValue is provided.

src/annotator/config/settings.js

@@ -84,7 +84,7 @@ export default function settingsFrom(window_) {
   function showHighlights() {
     let showHighlights_ = hostPageSetting('showHighlights');
 
-    if (showHighlights_ === null) {
+    if (showHighlights_ === undefined) {
       showHighlights_ = 'always'; // The default value is 'always'.
     }
 
@@ -128,9 +128,17 @@ export default function settingsFrom(window_) {
     return jsonConfigs.query || queryFromURL();
   }
 
-  function hostPageSetting(name, options = {}) {
-    const hasDefaultValue = typeof options.defaultValue !== 'undefined';
-
+  /**
+   * Returns the first setting value found from the respective sources in order.
+   *
+   *  1. window.hypothesisConfig()
+   *  2. <script class="js-hypothesis-config">
+   *
+   * If the setting is not found in either source, then return undefined.
+   *
+   * @param {string} name - Unique name of the setting
+   */
+  function hostPageSetting(name) {
     if (configFuncSettings.hasOwnProperty(name)) {
       return configFuncSettings[name];
     }
@@ -139,11 +147,7 @@ export default function settingsFrom(window_) {
       return jsonConfigs[name];
     }
 
-    if (hasDefaultValue) {
-      return options.defaultValue;
-    }
-
-    return null;
+    return undefined;
   }
 
   return {

src/annotator/config/test/settings-test.js

@@ -298,18 +298,15 @@ describe('annotator/config/settingsFrom', () => {
         input: 42,
         output: 42,
       },
-      // If the host page sets showHighlights to null this will be mistaken
-      // for the host page not containing a showHighlights setting at all and
-      // showHighlights will be set to 'always'.
       {
         it: 'defaults to "always"',
-        input: null,
+        input: undefined,
         output: 'always',
       },
       {
-        it: 'passes undefined through unmodified',
-        input: undefined,
-        output: undefined,
+        it: 'passes null through unmodified',
+        input: null,
+        output: null,
       },
       {
         it: 'passes arrays through unmodified',
@@ -367,7 +364,7 @@ describe('annotator/config/settingsFrom', () => {
         isBrowserExtension: false,
         configFuncSettings: { ignoreOtherConfiguration: '1' },
         jsonSettings: { foo: 'ignored' },
-        expected: null,
+        expected: undefined,
       },
       {
         when: 'the client is embedded in a web page',
@@ -400,41 +397,13 @@ describe('annotator/config/settingsFrom', () => {
         jsonSettings: { foo: 'jsonValue' },
         expected: undefined,
       },
-      {
-        when: 'no default value is provided',
-        specify: 'it returns null',
-        configFuncSettings: {},
-        jsonSettings: {},
-        defaultValue: undefined,
-        expected: null,
-      },
-      {
-        when: 'a default value is provided',
-        specify: 'it returns that default value',
-        configFuncSettings: {},
-        jsonSettings: {},
-        defaultValue: 'test value',
-        expected: 'test value',
-      },
-      {
-        when: 'a default value is provided but it is overridden',
-        specify: 'it returns the overridden value',
-        configFuncSettings: { foo: 'not the default value' },
-        jsonSettings: {},
-        defaultValue: 'the default value',
-        expected: 'not the default value',
-      },
     ].forEach(function (test) {
       context(test.when, () => {
         specify(test.specify, () => {
           fakeConfigFuncSettingsFrom.returns(test.configFuncSettings);
           fakeParseJsonConfig.returns(test.jsonSettings);
           const settings = settingsFrom(fakeWindow());
-
-          const setting = settings.hostPageSetting('foo', {
-            defaultValue: test.defaultValue || null,
-          });
-
+          const setting = settings.hostPageSetting('foo');
           assert.strictEqual(setting, test.expected);
         });
       });