fix(attr): Fix handling of undefined as value (#1582)

Fixes #554

This makes cheerio behave like jQuery with these values.

Tests were part of the issue above, contributed by @iwarren.

Co-authored-by: Ian Warren <warreia@gmail.com>

lib/api/attributes.js

@@ -86,7 +86,7 @@ var setAttr = function (el, name, value) {
  */
 exports.attr = function (name, value) {
  // Set the value (with attr map support)
- if (typeof name === 'object' || value !== undefined) {
+ if (typeof name === 'object' || arguments.length > 1) {
  if (typeof value === 'function') {
  return domEach(this, function (i, el) {
  setAttr(el, name, value.call(el, i, el.attribs[name]));
@@ -335,16 +335,13 @@ exports.val = function (value) {
  case 'textarea':
  return this.text(value);
  case 'input':
- if (this.attr('type') === 'radio') {
- if (querying) {
- return this.attr('value');
- }
-
- this.attr('value', value);
- return this;
+ if (querying) {
+ return this.attr('value');
  }
 
- return this.attr('value', value);
+ this.attr('value', value);
+ return this;
+
  case 'select':
  var option = this.find('option:selected');
  var returnValue;

test/api/attributes.js

@@ -137,6 +137,23 @@ describe('$(...)', function () {
  expect($pear.attr('autofocus')).to.be(undefined);
  expect($pear.attr('style')).to.equal('color:blue');
  });
+
+ it('(chaining) setting value and calling attr returns result', function () {
+ var pearAttr = $('.pear').attr('foo', 'bar').attr('foo');
+ expect(pearAttr).to.equal('bar');
+ });
+
+ it('(chaining) setting attr to null returns a $', function () {
+ var $pear = $('.pear').attr('foo', null);
+ expect($pear).to.be.a($);
+ });
+
+ it('(chaining) setting attr to undefined returns a $', function () {
+ var $pear = $('.pear').attr('foo', undefined);
+ expect($('.pear')).to.have.length(1);
+ expect($('.pear').attr('foo')).to.be('undefined');
+ expect($pear).to.be.a($);
+ });
  });
 
  describe('.prop', function () {