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perf: walk and serialize the tree without intermediate arrays #337

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763be36
perf(serialize): skip the escape pass when there is nothing to escape
zirkelc Sep 22, 2026
0082e49
perf(parent-node): build childNodes and children in one pass over the…
zirkelc Sep 22, 2026
a3af056
perf(element): build the serialized markup as one string
zirkelc Sep 22, 2026
642641f
perf(text): concatenate text content instead of joining arrays
zirkelc Sep 22, 2026
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3 changes: 2 additions & 1 deletion cjs/interface/attr.js
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Original file line number Diff line number Diff line change
Expand Up @@ -46,7 +46,8 @@ class Attr extends Node {
if (emptyAttributes.has(name) && !value) {
return ignoreCase(this) ? name : `${name}=""`;
}
const escapedValue = (ignoreCase(this) ? value : escape(value)).replace(QUOTE, '"');
const rawValue = ignoreCase(this) ? value : escape(value);
const escapedValue = rawValue.includes('"') ? rawValue.replace(QUOTE, '"') : rawValue;
return `${name}="${escapedValue}"`;
}

Expand Down
50 changes: 27 additions & 23 deletions cjs/interface/element.js
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Original file line number Diff line number Diff line change
Expand Up @@ -160,35 +160,35 @@ class Element extends ParentNode {

// <contentRelated>
get innerText() {
const text = [];
let text = '';
let {[NEXT]: next, [END]: end} = this;
while (next !== end) {
if (next.nodeType === TEXT_NODE) {
text.push(next.textContent.replace(/\s+/g, ' '));
text += next.textContent.replace(/\s+/g, ' ');
} else if(
text.length && next[NEXT] != end &&
BLOCK_ELEMENTS.has(next.tagName)
) {
text.push('\n');
text += '\n';
}
next = next[NEXT];
}
return text.join('');
return text;
}

/**
* @returns {String}
*/
get textContent() {
const text = [];
let text = '';
let {[NEXT]: next, [END]: end} = this;
while (next !== end) {
const nodeType = next.nodeType;
if (nodeType === TEXT_NODE || nodeType === CDATA_SECTION_NODE)
text.push(next.textContent);
text += next.textContent;
next = next[NEXT];
}
return text.join('');
return text;
}

set textContent(text) {
Expand Down Expand Up @@ -435,62 +435,66 @@ class Element extends ParentNode {

// <custom>
toString() {
const out = [];
// the output grows by concatenation: one rope beats an array of thousands of pieces
let out = '';
const {[END]: end} = this;
let next = {[NEXT]: this};
let isOpened = false;
do {
next = next[NEXT];
switch (next.nodeType) {
case ATTRIBUTE_NODE: {
const attr = ' ' + next;
const attr = next.toString();
switch (attr) {
case ' id':
case ' class':
case ' style':
case 'id':
case 'class':
case 'style':
break;
default:
out.push(attr);
out += ' ' + attr;
}
break;
}
case NODE_END: {
const start = next[START];
if (isOpened) {
if ('ownerSVGElement' in start)
out.push(' />');
out += ' />';
else if (isVoid(start))
out.push(ignoreCase(start) ? '>' : ' />');
out += ignoreCase(start) ? '>' : ' />';
else
out.push(`></${start.localName}>`);
out += `></${start.localName}>`;
isOpened = false;
}
else
out.push(`</${start.localName}>`);
out += `</${start.localName}>`;
break;
}
case ELEMENT_NODE:
if (isOpened)
out.push('>');
out += '>';
if (next.toString !== this.toString) {
out.push(next.toString());
out += next.toString();
next = next[END];
isOpened = false;
}
else {
out.push(`<${next.localName}`);
out += `<${next.localName}`;
isOpened = true;
}
break;
case TEXT_NODE:
case COMMENT_NODE:
case CDATA_SECTION_NODE:
out.push((isOpened ? '>' : '') + next);
isOpened = false;
if (isOpened) {
out += '>';
isOpened = false;
}
out += next;
break;
}
} while (next !== end);
return out.join('');
return out;
}

toJSON() {
Expand Down
10 changes: 5 additions & 5 deletions cjs/interface/text.js
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Original file line number Diff line number Diff line change
Expand Up @@ -14,24 +14,24 @@ class Text extends CharacterData {
}

get wholeText() {
const text = [];
let {previousSibling, nextSibling} = this;
let text = '';
while (previousSibling) {
if (previousSibling.nodeType === TEXT_NODE)
text.unshift(previousSibling[VALUE]);
text = previousSibling[VALUE] + text;
else
break;
previousSibling = previousSibling.previousSibling;
}
text.push(this[VALUE]);
text += this[VALUE];
while (nextSibling) {
if (nextSibling.nodeType === TEXT_NODE)
text.push(nextSibling[VALUE]);
text += nextSibling[VALUE];
else
break;
nextSibling = nextSibling.nextSibling;
}
return text.join('');
return text;
}

cloneNode() {
Expand Down
35 changes: 25 additions & 10 deletions cjs/mixin/parent-node.js
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Original file line number Diff line number Diff line change
Expand Up @@ -25,8 +25,6 @@ const {NodeList} = require('../interface/node-list.js');
const {moCallback} = require('../interface/mutation-observer.js');
const {connectedCallback} = require('../interface/custom-element-registry.js');

const {nextElementSibling} = require('./non-document-type-child-node.js');

const isNode = node => node instanceof Node;

const insert = (parentNode, child, nodes) => {
Expand Down Expand Up @@ -64,20 +62,37 @@ class ParentNode extends Node {

get childNodes() {
const childNodes = new NodeList;
let {firstChild} = this;
while (firstChild) {
childNodes.push(firstChild);
firstChild = nextSibling(firstChild);
// walk the list once: an element is followed by its whole subtree, so jump over it
const {[END]: end} = this;
let next = this[NEXT];
while (next !== end) {
switch (next.nodeType) {
case ATTRIBUTE_NODE:
next = next[NEXT];
break;
case ELEMENT_NODE:
childNodes.push(next);
next = next[END][NEXT];
break;
default:
childNodes.push(next);
next = next[NEXT];
}
}
return childNodes;
}

get children() {
const children = new NodeList;
let {firstElementChild} = this;
while (firstElementChild) {
children.push(firstElementChild);
firstElementChild = nextElementSibling(firstElementChild);
const {[END]: end} = this;
let next = this[NEXT];
while (next !== end) {
if (next.nodeType === ELEMENT_NODE) {
children.push(next);
next = next[END][NEXT];
}
else
next = next[NEXT];
}
return children;
}
Expand Down
4 changes: 3 additions & 1 deletion cjs/shared/text-escaper.js
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@ const {replace} = '';

// escape
const ca = /[<>&\xA0]/g;
// same characters, without the global flag: `test` on a global regex moves lastIndex
const needsEscape = /[<>&\xA0]/;

const esca = {
'\xA0': '&#160;',
Expand All @@ -20,5 +22,5 @@ const pe = m => esca[m];
* the input type is unexpected, except for boolean and numbers,
* converted as string.
*/
const escape = es => replace.call(es, ca, pe);
const escape = es => needsEscape.test(es) ? replace.call(es, ca, pe) : es;
exports.escape = escape;
3 changes: 2 additions & 1 deletion esm/interface/attr.js
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,8 @@ export class Attr extends Node {
if (emptyAttributes.has(name) && !value) {
return ignoreCase(this) ? name : `${name}=""`;
}
const escapedValue = (ignoreCase(this) ? value : escape(value)).replace(QUOTE, '&quot;');
const rawValue = ignoreCase(this) ? value : escape(value);
const escapedValue = rawValue.includes('"') ? rawValue.replace(QUOTE, '&quot;') : rawValue;
return `${name}="${escapedValue}"`;
}

Expand Down
50 changes: 27 additions & 23 deletions esm/interface/element.js
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Original file line number Diff line number Diff line change
Expand Up @@ -162,35 +162,35 @@ export class Element extends ParentNode {

// <contentRelated>
get innerText() {
const text = [];
let text = '';
let {[NEXT]: next, [END]: end} = this;
while (next !== end) {
if (next.nodeType === TEXT_NODE) {
text.push(next.textContent.replace(/\s+/g, ' '));
text += next.textContent.replace(/\s+/g, ' ');
} else if(
text.length && next[NEXT] != end &&
BLOCK_ELEMENTS.has(next.tagName)
) {
text.push('\n');
text += '\n';
}
next = next[NEXT];
}
return text.join('');
return text;
}

/**
* @returns {String}
*/
get textContent() {
const text = [];
let text = '';
let {[NEXT]: next, [END]: end} = this;
while (next !== end) {
const nodeType = next.nodeType;
if (nodeType === TEXT_NODE || nodeType === CDATA_SECTION_NODE)
text.push(next.textContent);
text += next.textContent;
next = next[NEXT];
}
return text.join('');
return text;
}

set textContent(text) {
Expand Down Expand Up @@ -437,62 +437,66 @@ export class Element extends ParentNode {

// <custom>
toString() {
const out = [];
// the output grows by concatenation: one rope beats an array of thousands of pieces
let out = '';
const {[END]: end} = this;
let next = {[NEXT]: this};
let isOpened = false;
do {
next = next[NEXT];
switch (next.nodeType) {
case ATTRIBUTE_NODE: {
const attr = ' ' + next;
const attr = next.toString();
switch (attr) {
case ' id':
case ' class':
case ' style':
case 'id':
case 'class':
case 'style':
break;
default:
out.push(attr);
out += ' ' + attr;
}
break;
}
case NODE_END: {
const start = next[START];
if (isOpened) {
if ('ownerSVGElement' in start)
out.push(' />');
out += ' />';
else if (isVoid(start))
out.push(ignoreCase(start) ? '>' : ' />');
out += ignoreCase(start) ? '>' : ' />';
else
out.push(`></${start.localName}>`);
out += `></${start.localName}>`;
isOpened = false;
}
else
out.push(`</${start.localName}>`);
out += `</${start.localName}>`;
break;
}
case ELEMENT_NODE:
if (isOpened)
out.push('>');
out += '>';
if (next.toString !== this.toString) {
out.push(next.toString());
out += next.toString();
next = next[END];
isOpened = false;
}
else {
out.push(`<${next.localName}`);
out += `<${next.localName}`;
isOpened = true;
}
break;
case TEXT_NODE:
case COMMENT_NODE:
case CDATA_SECTION_NODE:
out.push((isOpened ? '>' : '') + next);
isOpened = false;
if (isOpened) {
out += '>';
isOpened = false;
}
out += next;
break;
}
} while (next !== end);
return out.join('');
return out;
}

toJSON() {
Expand Down
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