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Add tests for Range collapse ordering in deleteContents/extractContents #58008

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Add tests for Range collapse ordering in deleteContents/extractContents
stevenobiajulu Feb 24, 2026
941dea7
Add disconnectedCallback mutation tests for deleteContents/extractCon…
stevenobiajulu Mar 11, 2026
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110 changes: 110 additions & 0 deletions dom/ranges/Range-deleteContents-mutation-order.html
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<!doctype html>
<title>Range.deleteContents() collapses range before mutations</title>
<link rel="author" title="Steven Obiajulu" href="https://github.com/stevenobiajulu">
<link rel="help" href="https://dom.spec.whatwg.org/#dom-range-deletecontents">
<meta name="assert" content="Range.deleteContents() sets range start and end before performing mutations, so the range remains valid even if script runs during removal.">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<script>
"use strict";

// Case 1: originalStartNode is an inclusive ancestor of originalEndNode.
// The range should collapse to (originalStartNode, originalStartOffset).
test(function() {
const div = document.createElement("div");
for (let i = 0; i < 5; i++) {
div.appendChild(document.createElement("span"));
}
// Range: (div, 2) to (div, 5) — covers children at indices 2, 3, 4.
const range = document.createRange();
range.setStart(div, 2);
range.setEnd(div, 5);

range.deleteContents();

assert_equals(range.startContainer, div, "startContainer should be div");
assert_equals(range.startOffset, 2, "startOffset should be 2");
assert_equals(range.endContainer, div, "endContainer should be div");
assert_equals(range.endOffset, 2, "endOffset should be 2");
assert_true(range.collapsed, "range should be collapsed");
assert_equals(div.childNodes.length, 2, "div should have 2 remaining children");
}, "deleteContents collapses range correctly when start is ancestor of end (element children)");

// Case 2: originalStartNode is NOT an inclusive ancestor of originalEndNode.
// The range should collapse to (referenceNode.parent, referenceNode.index + 1).
test(function() {
const div = document.createElement("div");
const referenceSpan = document.createElement("span");
const n1 = document.createElement("span");
const n2 = document.createElement("span");
const n3 = document.createElement("span");
const endSpan = document.createElement("span");
div.append(referenceSpan, n1, n2, n3, endSpan);
// Place start inside referenceSpan, end inside endSpan.
referenceSpan.appendChild(document.createTextNode("start"));
endSpan.appendChild(document.createTextNode("end"));

const range = document.createRange();
range.setStart(referenceSpan.firstChild, 2);
range.setEnd(endSpan.firstChild, 1);

range.deleteContents();

// newNode = div (parent of referenceSpan), newOffset = 1 (referenceSpan.index + 1).
// After removals of n1, n2, n3, the range should be auto-maintained to a valid position.
assert_true(range.collapsed, "range should be collapsed");
assert_equals(range.startContainer, div, "startContainer should be div");
// After removing n1, n2, n3 (which were at indices 1, 2, 3), and with
// live range pre-remove steps adjusting the offset, the final offset
// should be 1 (the original offset, since removed nodes were at index >= offset).
assert_equals(range.startOffset, 1, "startOffset should be 1");
}, "deleteContents collapses range correctly when start is not ancestor of end");

// Case 3: CharacterData start and end nodes (partial text deletion).
test(function() {
const div = document.createElement("div");
const startText = document.createTextNode("Hello");
const middleSpan = document.createElement("span");
const endText = document.createTextNode("World");
div.append(startText, middleSpan, endText);

const range = document.createRange();
range.setStart(startText, 2); // "He|llo"
range.setEnd(endText, 3); // "Wor|ld"

range.deleteContents();

assert_true(range.collapsed, "range should be collapsed");
// newNode = startText (originalStartNode is inclusive ancestor since it's the start text).
// Wait — startText is NOT an inclusive ancestor of endText. So we go to the "otherwise" branch.
// referenceNode walks up from startText. startText's parent is div, which IS an ancestor
// of endText. So referenceNode stays at startText.
// newNode = div, newOffset = startText.index + 1 = 1.
// After replace data of startText (truncates "Hello" to "He"), remove middleSpan,
// replace data of endText (truncates "World" to "ld"), the range should be valid.
assert_equals(range.startContainer, div, "startContainer should be div");
assert_equals(range.startOffset, 1, "startOffset should be 1");
assert_equals(startText.data, "He", "start text should be truncated");
assert_equals(endText.data, "ld", "end text should be truncated");
assert_equals(div.childNodes.length, 2, "middle span should be removed");
}, "deleteContents collapses range correctly with CharacterData boundary nodes");

// Case 4: Same CharacterData node (early return path — no mutation ordering issue).
test(function() {
const div = document.createElement("div");
const text = document.createTextNode("Hello World");
div.appendChild(text);

const range = document.createRange();
range.setStart(text, 2);
range.setEnd(text, 7);

range.deleteContents();

assert_true(range.collapsed, "range should be collapsed");
assert_equals(range.startContainer, text, "startContainer should be the text node");
assert_equals(range.startOffset, 2, "startOffset should be 2");
assert_equals(text.data, "Heorld", "text data should have middle removed");
}, "deleteContents handles same CharacterData node correctly");
</script>
101 changes: 101 additions & 0 deletions dom/ranges/Range-extractContents-mutation-order.html
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<!doctype html>
<title>Range.extractContents() collapses range before mutations</title>
<link rel="author" title="Steven Obiajulu" href="https://github.com/stevenobiajulu">
<link rel="help" href="https://dom.spec.whatwg.org/#concept-range-extract">
<meta name="assert" content="The extract algorithm sets range start and end before performing mutations, so the range remains valid even if script runs during removal.">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<script>
"use strict";

// Case 1: originalStartNode is an inclusive ancestor of originalEndNode.
// The range should collapse to (originalStartNode, originalStartOffset).
test(function() {
const div = document.createElement("div");
for (let i = 0; i < 5; i++) {
div.appendChild(document.createElement("span"));
}
// Range: (div, 2) to (div, 5) — covers children at indices 2, 3, 4.
const range = document.createRange();
range.setStart(div, 2);
range.setEnd(div, 5);

const fragment = range.extractContents();

assert_equals(range.startContainer, div, "startContainer should be div");
assert_equals(range.startOffset, 2, "startOffset should be 2");
assert_equals(range.endContainer, div, "endContainer should be div");
assert_equals(range.endOffset, 2, "endOffset should be 2");
assert_true(range.collapsed, "range should be collapsed");
assert_equals(div.childNodes.length, 2, "div should have 2 remaining children");
assert_equals(fragment.childNodes.length, 3, "fragment should contain 3 extracted children");
}, "extractContents collapses range correctly when start is ancestor of end (element children)");

// Case 2: originalStartNode is NOT an inclusive ancestor of originalEndNode.
// The range should collapse to (referenceNode.parent, referenceNode.index + 1).
test(function() {
const div = document.createElement("div");
const referenceSpan = document.createElement("span");
const n1 = document.createElement("span");
const n2 = document.createElement("span");
const n3 = document.createElement("span");
const endSpan = document.createElement("span");
div.append(referenceSpan, n1, n2, n3, endSpan);
referenceSpan.appendChild(document.createTextNode("start"));
endSpan.appendChild(document.createTextNode("end"));

const range = document.createRange();
range.setStart(referenceSpan.firstChild, 2);
range.setEnd(endSpan.firstChild, 1);

const fragment = range.extractContents();

assert_true(range.collapsed, "range should be collapsed");
assert_equals(range.startContainer, div, "startContainer should be div");
assert_equals(range.startOffset, 1, "startOffset should be 1");
assert_true(fragment.childNodes.length > 0, "fragment should have extracted content");
}, "extractContents collapses range correctly when start is not ancestor of end");

// Case 3: CharacterData start and end nodes (partial text extraction).
test(function() {
const div = document.createElement("div");
const startText = document.createTextNode("Hello");
const middleSpan = document.createElement("span");
const endText = document.createTextNode("World");
div.append(startText, middleSpan, endText);

const range = document.createRange();
range.setStart(startText, 2); // "He|llo"
range.setEnd(endText, 3); // "Wor|ld"

const fragment = range.extractContents();

assert_true(range.collapsed, "range should be collapsed");
assert_equals(range.startContainer, div, "startContainer should be div");
assert_equals(range.startOffset, 1, "startOffset should be 1");
assert_equals(startText.data, "He", "start text should be truncated");
assert_equals(endText.data, "ld", "end text should be truncated");
assert_equals(div.childNodes.length, 2, "middle span should be extracted");
assert_true(fragment.childNodes.length > 0, "fragment should contain extracted content");
}, "extractContents collapses range correctly with CharacterData boundary nodes");

// Case 4: Same CharacterData node (early return path — no mutation ordering issue).
test(function() {
const div = document.createElement("div");
const text = document.createTextNode("Hello World");
div.appendChild(text);

const range = document.createRange();
range.setStart(text, 2);
range.setEnd(text, 7);

const fragment = range.extractContents();

assert_true(range.collapsed, "range should be collapsed");
assert_equals(range.startContainer, text, "startContainer should be the text node");
assert_equals(range.startOffset, 2, "startOffset should be 2");
assert_equals(text.data, "Heorld", "text data should have middle removed");
assert_equals(fragment.firstChild.data, "llo W", "fragment should contain extracted text");
}, "extractContents handles same CharacterData node correctly");
</script>