Allow modification of existing attributes and text content.

src/attributes.ts

@@ -8,6 +8,8 @@ import type {Element} from './nodeTypes.js';
  * @return {void}
  */
 export function setAttribute(node: Element, name: string, value: string): void {
+  removeAttribute(node, name);
+
   node.attrs.push({
     name,
     value

src/test/attributes_test.ts

@@ -19,6 +19,22 @@ test('setAttribute', async (t) => {
 
     assert.deepStrictEqual(node.attrs, [{name: 'ping-pong', value: 'boing'}]);
   });
+
+  await t.test('modifies existing attribute on element', () => {
+    const node: Element = {
+      nodeName: 'div',
+      parentNode: null,
+      tagName: 'div',
+      attrs: [{name: 'foo', value: 'bar'}],
+      namespaceURI: html.NS.HTML,
+      childNodes: []
+    };
+
+    main.setAttribute(node, 'foo', 'baz');
+
+    assert.strictEqual(node.attrs.length, 1);
+    assert.deepStrictEqual(node.attrs, [{name: 'foo', value: 'baz'}]);
+  });
 });
 
 test('getAttribute', async (t) => {

src/test/text_test.ts

@@ -35,16 +35,28 @@ test('getTextContent', async (t) => {
     assert.strictEqual(result, 'some text');
   });
 
+  await t.test('returns value of comment node', () => {
+    const node: CommentNode = {
+      nodeName: '#comment',
+      parentNode: null,
+      data: 'some comment'
+    };
+
+    const result = main.getTextContent(node);
+
+    assert.strictEqual(result, 'some comment');
+  });
+
   await t.test('concats all text-like children', () => {
     const child1: TextNode = {
       nodeName: '#text',
       parentNode: null,
-      value: 'text node'
+      value: 'text node 1'
     };
-    const child2: CommentNode = {
-      nodeName: '#comment',
+    const child2: TextNode = {
+      nodeName: '#text',
       parentNode: null,
-      data: 'comment node'
+      value: 'text node 2'
     };
     const node: DocumentFragment = {
       nodeName: '#document-fragment',
@@ -53,7 +65,7 @@ test('getTextContent', async (t) => {
 
     const result = main.getTextContent(node);
 
-    assert.strictEqual(result, 'text nodecomment node');
+    assert.strictEqual(result, 'text node 1text node 2');
   });
 
   await t.test('ignores non-text children', () => {
@@ -164,6 +176,28 @@ test('setTextContent', async (t) => {
     });
   });
 
+  await t.test('sets text node for parent nodes', () => {
+    const node: DocumentFragment = {
+      nodeName: '#document-fragment',
+      childNodes: []
+    };
+
+    node.childNodes.push({
+      nodeName: '#text',
+      value: 'old text',
+      parentNode: node
+    });
+
+    main.setTextContent(node, 'new text');
+
+    assert.strictEqual(node.childNodes.length, 1);
+    assert.deepStrictEqual(node.childNodes[0], {
+      nodeName: '#text',
+      value: 'new text',
+      parentNode: node
+    });
+  });
+
   await t.test('ignores document type nodes', () => {
     const node: DocumentType = {
       nodeName: '#documentType',

src/text.ts

@@ -1,8 +1,8 @@
 import type {Node} from './nodeTypes.js';
 import {isCommentNode, isTextNode, isParentNode} from './typeGuards.js';
-import {appendChild} from './treeMutation.js';
 import {createTextNode} from './creation.js';
 import {queryAll} from './traversal.js';
+import {appendChild} from './treeMutation.js';
 
 /**
  * Computes the text content of a given node using a similar
@@ -21,10 +21,7 @@ export function getTextContent(node: Node): string {
 
   let content = '';
 
-  const children = queryAll(
-    node,
-    (node) => isTextNode(node) || isCommentNode(node)
-  );
+  const children = queryAll(node, (node) => isTextNode(node));
 
   for (const child of children) {
     content += getTextContent(child);
@@ -45,7 +42,7 @@ export function setTextContent(node: Node, text: string): void {
   } else if (isTextNode(node)) {
     node.value = text;
   } else if (isParentNode(node)) {
-    const textNode = createTextNode(text);
-    appendChild(node, textNode);
+    node.childNodes = [];
+    appendChild(node, createTextNode(text));
   }
 }