Added Formset.prototype.prefixFormat

Added API docs for prefixFormat.

Closes #70

CHANGES.md

@@ -19,6 +19,11 @@
 * Added new core `Field` argument: `field.widgetAttrs` - this allows you to
   provide additional widget attributes without having to redefine the entire
   widget ([#62](https://github.com/insin/newforms/issues/62))
+* Added `Form.prototype.prefixFormat` (`'{prefix}-{name}'`) and
+  `FormSet.prototype.prefixFormat` (`'{prefix}-{index}'`) to define how prefixes
+  are generated. These can be overridden when extending these components to
+  customise now field names are generated when prefixes are used
+  ([#70](https://github.com/insin/newforms/issues/70))
 
 ## Changes
 

docs/forms_api.rst

@@ -138,6 +138,18 @@ Forms API
    :param Boolean kwargs.emptyPermitted:
       if ``true``, the form is allowed to be empty -- defaults to ``false``.
 
+   **Prototype Properties**
+
+   .. js:attribute:: Form#prefixFormat
+
+      This string defines the format used to generate ``name`` attributes for
+      fields when a form instance is given a ``prefix``. It must contain
+      ``{prefix}`` and ``{name}`` placeholders.
+
+      The default format is ``'{prefix}-{name}'``.
+
+      :type String:
+
    **Instance Properties**
 
    Form options documented in ``kwargs`` above are all set as instance

docs/formsets_api.rst

@@ -116,6 +116,18 @@ Formsets API
       :param Object constructorProps:
          properties to be set directly on the new constructor function.
 
+   **Prototype Properties**
+
+   .. js:attribute:: FormSet#prefixFormat
+
+      This string defines the format used to generate a ``prefix`` for forms in
+      the formset to ensure they have unique ``name`` attributes. It must
+      contain ``{prefix}`` and ``{index}`` placeholders.
+
+      The default format is ``'{prefix}-{index}'``.
+
+      :type String:
+
    **Instance Properties**
 
    Formset options documented in ``kwargs`` above are set as instance properties.

src/FormSet.js

@@ -3,6 +3,7 @@
 var Concur = require('Concur')
 var getFormData = require('get-form-data')
 var is = require('isomorph/is')
+var {formatObj} = require('isomorph/format')
 var object = require('isomorph/object')
 
 var constants = require('./constants')
@@ -61,6 +62,8 @@ var ManagementForm = (function() {
  * @param {Object=} kwargs
  */
 var FormSet = Concur.extend({
+  prefixFormat: '{prefix}-{index}',
+
   constructor: function FormSet(kwargs) {
     // TODO Perform PropType checks on kwargs in development mode
     kwargs = object.extend({
@@ -897,7 +900,7 @@ FormSet.prototype.nonFormPending = function() {
  * @param {Number} index the index of a form in the formset.
  */
 FormSet.prototype.addPrefix = function(index) {
-  return this.prefix + '-' + index
+  return formatObj(this.prefixFormat, {prefix: this.prefix, index: index})
 }
 
 FormSet.prototype.getDefaultPrefix = function() {

tests/formsets-server.js

@@ -80,6 +80,34 @@ QUnit.test("Basic FormSet", 5, function() {
   strictEqual(formset.hasChanged(), false)
 })
 
+QUnit.test('Custom prefix format', function() {
+  // By default, formsets append a hyphen between the prefix and theform index,
+  // but a formset can alter that behaviour by overriding prefixFormat, which
+  // should be a string containing {prefix} and {index} placeholders.
+  var ChoiceForm = forms.Form.extend({
+    prefixFormat: '{prefix}[{name}]',
+    choice: forms.CharField(),
+    votes: forms.IntegerField()
+  })
+
+  var ChoiceFormSet = forms.FormSet.extend({
+    form: ChoiceForm,
+    prefixFormat: '{prefix}[{index}]'
+  })
+
+  var initial = [{choice: "Calexico", votes: 100}]
+  var formset = new ChoiceFormSet({initial: initial, autoId: false, prefix: 'choices'})
+  reactHTMLEqual(renderAll(formset.forms()),
+'<div>\
+<div>Choice: <input type="text" name="choices[0][choice]" value="Calexico"></div>\
+<div>Votes: <input type="number" name="choices[0][votes]" value="100"></div>\
+</div>\
+<div>\
+<div>Choice: <input type="text" name="choices[1][choice]"></div>\
+<div>Votes: <input type="number" name="choices[1][votes]"></div>\
+</div>')
+})
+
 QUnit.test("Formset validation", 2, function() {
   // FormSet instances can also have an error attribute if validation failed for
   // any of the forms.