fix: parsing and stringify empty attribute value

Author: alexander-akait

src/__tests__/attributes.js

@@ -63,6 +63,13 @@ test('namespace with escapes', '[\\31 \\#\\32 |href]', (t, tree) => {
     t.deepEqual(attr.raws.namespace, '\\31');
 });
 
+test('attribute selector with a empty value', '[href=""]', (t, tree) => {
+    t.deepEqual(tree.nodes[0].nodes[0].attribute, 'href');
+    t.deepEqual(tree.nodes[0].nodes[0].operator, '=');
+    t.deepEqual(tree.nodes[0].nodes[0].value, '');
+    t.true(tree.nodes[0].nodes[0].quoted);
+});
+
 test('attribute selector with a value', '[name=james]', (t, tree) => {
     t.deepEqual(tree.nodes[0].nodes[0].attribute, 'name');
     t.deepEqual(tree.nodes[0].nodes[0].operator, '=');
@@ -327,6 +334,14 @@ test('insensitive attribute selector 1', '[href="test" i]', (t, tree) => {
     t.deepEqual(tree.nodes[0].nodes[0].insensitive, true);
 });
 
+test('insensitive attribute selector with a empty value', '[href="" i]', (t, tree) => {
+    t.deepEqual(tree.nodes[0].nodes[0].attribute, 'href');
+    t.deepEqual(tree.nodes[0].nodes[0].operator, '=');
+    t.deepEqual(tree.nodes[0].nodes[0].value, '');
+    t.deepEqual(tree.nodes[0].nodes[0].insensitive, true);
+    t.true(tree.nodes[0].nodes[0].quoted);
+});
+
 test('insensitive attribute selector 2', '[href=TEsT i  ]', (t, tree) => {
     t.deepEqual(tree.nodes[0].nodes[0].value, 'TEsT');
     t.deepEqual(tree.nodes[0].nodes[0].insensitive, true);

src/parser.js

@@ -287,7 +287,7 @@ export default class Parser {
                         node.raws.attribute += content;
                     }
                     lastAdded = 'attribute';
-                } else if (!node.value || (lastAdded === "value" && !spaceAfterMeaningfulToken)) {
+                } else if ((!node.value && node.value !== "") || (lastAdded === "value" && !spaceAfterMeaningfulToken)) {
                     let unescaped = unesc(content);
                     let oldRawValue = getProp(node, 'raws', 'value') || '';
                     let oldValue = node.value || '';
@@ -300,7 +300,7 @@ export default class Parser {
                     lastAdded = 'value';
                 } else {
                     let insensitive = (content === 'i' || content === "I");
-                    if (node.value && (node.quoteMark || spaceAfterMeaningfulToken)) {
+                    if ((node.value || node.value === '') && (node.quoteMark || spaceAfterMeaningfulToken)) {
                         node.insensitive = insensitive;
                         if (!insensitive || content === "I") {
                             ensureObject(node, 'raws');
@@ -318,7 +318,7 @@ export default class Parser {
                             node.raws.spaces.insensitive.before = commentBefore;
                             commentBefore = '';
                         }
-                    } else if (node.value) {
+                    } else if (node.value || node.value === '') {
                         lastAdded = 'value';
                         node.value += content;
                         if (node.raws.value) {

src/selectors/attribute.js

@@ -372,14 +372,15 @@ export default class Attribute extends Namespace {
 
         selector.push(this._stringFor('qualifiedAttribute', 'attribute'));
 
-        if (this.operator && this.value) {
+        if (this.operator && (this.value || this.value === '')) {
             selector.push(this._stringFor('operator'));
             selector.push(this._stringFor('value'));
             selector.push(this._stringFor('insensitiveFlag', 'insensitive', (attrValue, attrSpaces) => {
                 if (attrValue.length > 0
                     && !this.quoted
                     && attrSpaces.before.length === 0
                     && !(this.spaces.value && this.spaces.value.after)) {
+
                     attrSpaces.before = " ";
                 }
                 return defaultAttrConcat(attrValue, attrSpaces);