add general array container defaults handler

Author: etpinard

src/plots/array_container_defaults.js

@@ -0,0 +1,65 @@
+/**
+* Copyright 2012-2016, Plotly, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the MIT license found in the
+* LICENSE file in the root directory of this source tree.
+*/
+
+'use strict';
+
+var Lib = require('../lib');
+
+
+/** Convenience wrapper for making array container logic DRY and consistent
+ *
+ * @param {object} parentObjIn
+ *  user input object where the container in question is linked
+ *  (i.e. either a user trace object or the user layout object)
+ *
+ * @param {object} parentObjOut
+ *  full object where the coerced container will be linked
+ *  (i.e. either a full trace object or the full layout object)
+ *
+ * @param {object} opts
+ *  options object:
+ *   - name {string}
+ *      name of the key linking the container in question
+ *   - handleItemDefaults {function}
+ *      defaults method to be called on each item in the array container in question,
+ *
+ * N.B.
+ *
+ *  - opts is passed to handleItemDefaults so it can also store
+ *    links to supplementary data (e.g. fullData for layout components)
+ *
+ *  - opts.itemIsNotPlainObject is mutated on every pass in case so logic
+ *    in handleItemDefaults relies on that fact.
+ *
+ */
+module.exports = function handleArrayContainerDefaults(parentObjIn, parentObjOut, opts) {
+    var name = opts.name;
+
+    var contIn = Array.isArray(parentObjIn[name]) ? parentObjIn[name] : [],
+        contOut = parentObjOut[name] = [];
+
+    for(var i = 0; i < contIn.length; i++) {
+        var itemIn = contIn[i],
+            itemOut = {};
+
+        if(!Lib.isPlainObject(itemIn)) {
+            opts.itemIsNotPlainObject = true;
+            itemIn = {};
+        }
+        else {
+            opts.itemIsNotPlainObject = false;
+        }
+
+        opts.handleItemDefaults(itemIn, itemOut, parentObjOut, opts);
+
+        itemOut._input = itemIn;
+        itemOut._index = i;
+
+        contOut.push(itemOut);
+    }
+};