#77 - Allow claySettings to be modified from app.js (#150)

* .setSettings(key, value) to set a single setting
* .setSettings(object) to set multiple settings at once

index.js

@@ -213,6 +213,39 @@ Clay.prototype.getSettings = function(response, convert) {
   return convert === false ? settings : Clay.prepareSettingsForAppMessage(settings);
 };
 
+/**
+ * Updates the settings with the given value(s).
+ *
+ * @signature `clay.setSettings(key, value)`
+ * @param {String} key the property to set.
+ * @param {String} value the value assigned to _key_.
+ * @return {undefined}
+ *
+ * @signature `clay.setSettings(setting)`
+ * @param {Object} setting an object containing the key/value pairs to be set.
+ * @return {undefined}
+ */
+Clay.prototype.setSettings = function(key, value) {
+  var settingsStorage = {};
+
+  try {
+    settingsStorage = JSON.parse(localStorage.getItem('clay-settings')) || {};
+  } catch (e) {
+    console.error(e.toString());
+  }
+
+  if (typeof key === 'object') {
+    var settings = key;
+    Object.keys(settings).forEach(function(key) {
+      settingsStorage[key] = settings[key];
+    });
+  } else {
+    settingsStorage[key] = value;
+  }
+
+  localStorage.setItem('clay-settings', JSON.stringify(settingsStorage));
+};
+
 /**
  * @param {string} input
  * @param {string} [prefix='data:text/html;charset=utf-8,']

test/spec/index.js

@@ -386,6 +386,54 @@ describe('Clay', function() {
     });
   });
 
+  describe('.setSettings', function() {
+    it('it writes to localStorage when passing an object',
+      function() {
+        var clay = fixture.clay([]);
+        var settings = {
+          key1: 'value1',
+          key2: 'value2'
+        };
+        var expected = {
+          key1: 'value1',
+          key2: 'value2'
+        };
+
+        clay.setSettings(settings);
+        assert.equal(
+          localStorage.getItem('clay-settings'),
+          JSON.stringify(expected)
+        );
+      });
+
+    it('it writes to localStorage when passing a key and a value',
+      function() {
+        var clay = fixture.clay([]);
+        var expected = {
+          key1: 'value1',
+          key2: 'value2%7Dbreaks'
+        };
+
+        clay.setSettings('key1', 'value1');
+        clay.setSettings('key2', 'value2%7Dbreaks');
+        assert.equal(localStorage.getItem('clay-settings'),
+          JSON.stringify(expected)
+        );
+      });
+
+    it('doesn\'t throw and logs an error if settings in localStorage are broken',
+      function() {
+        var clay = fixture.clay([]);
+        var errorStub = sinon.stub(console, 'error');
+        localStorage.setItem('clay-settings', 'not valid JSON');
+        assert.doesNotThrow(function() {
+          clay.setSettings('key', 'value');
+        });
+        assert(errorStub.calledWithMatch(/SyntaxError/i));
+        errorStub.restore();
+      });
+  });
+
   describe('.meta', function() {
     var emptyMeta = {
       activeWatchInfo: null,