Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Performance improvements! #192

Merged
merged 2 commits into from
Mar 25, 2021
Merged

Performance improvements! #192

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b6aa5a7
Performance improvements!
developit Mar 20, 2021
95e4bc8
Reintroduce Fragment optimization
developit Mar 25, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
81 changes: 44 additions & 37 deletions src/index.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,9 @@ import {
assign,
getChildren
} from './util';
import { options, Fragment, createElement } from 'preact';
import { options, Fragment } from 'preact';

/** @typedef {import('preact').VNode} VNode */

const SHALLOW = { shallow: true };

Expand All @@ -28,7 +30,7 @@ const noop = () => {};
* @param {Boolean} [options.shallow=false] If `true`, renders nested Components as HTML elements (`<Foo a="b" />`).
* @param {Boolean} [options.xml=false] If `true`, uses self-closing tags for elements without children.
* @param {Boolean} [options.pretty=false] If `true`, adds whitespace for readability
* @param {RegEx|undefined} [options.voidElements] RegeEx that matches elements that are considered void (self-closing)
* @param {RegExp|undefined} [options.voidElements] RegeEx that matches elements that are considered void (self-closing)
*/
renderToString.render = renderToString;

Expand All @@ -43,6 +45,8 @@ let shallowRender = (vnode, context) => renderToString(vnode, context, SHALLOW);

const EMPTY_ARR = [];
function renderToString(vnode, context, opts) {
context = context || {};
opts = opts || {};
const res = _renderToString(vnode, context, opts);
// options._commit, we don't schedule any effects in this library right now,
// so we can pass an empty queue to this hook.
Expand All @@ -56,48 +60,50 @@ function _renderToString(vnode, context, opts, inner, isSvgMode, selectValue) {
return '';
}

// wrap array nodes in Fragment
if (Array.isArray(vnode)) {
vnode = createElement(Fragment, null, vnode);
// #text nodes
if (typeof vnode !== 'object') {
return encodeEntities(vnode);
}

let nodeName = vnode.type,
props = vnode.props,
isComponent = false;
context = context || {};
opts = opts || {};

let pretty = opts.pretty,
indentChar = pretty && typeof pretty === 'string' ? pretty : '\t';

// #text nodes
if (typeof vnode !== 'object' && !nodeName) {
return encodeEntities(vnode);
if (Array.isArray(vnode)) {
let rendered = '';
for (let i = 0; i < vnode.length; i++) {
if (pretty && i > 0) rendered += '\n';
rendered += _renderToString(
vnode[i],
context,
opts,
inner,
isSvgMode,
selectValue
);
}
return rendered;
}

let nodeName = vnode.type,
props = vnode.props,
isComponent = false;

// components
if (typeof nodeName === 'function') {
isComponent = true;
if (opts.shallow && (inner || opts.renderRootComponent === false)) {
nodeName = getComponentName(nodeName);
} else if (nodeName === Fragment) {
let rendered = '';
let children = [];
const children = [];
getChildren(children, vnode.props.children);

for (let i = 0; i < children.length; i++) {
rendered +=
(i > 0 && pretty ? '\n' : '') +
_renderToString(
children[i],
context,
opts,
opts.shallowHighOrder !== false,
isSvgMode,
selectValue
);
}
return rendered;
return _renderToString(
children,
context,
opts,
opts.shallowHighOrder !== false,
isSvgMode,
selectValue
);
} else {
let rendered;

Expand Down Expand Up @@ -197,7 +203,7 @@ function _renderToString(vnode, context, opts, inner, isSvgMode, selectValue) {
}

// render JSX to HTML
let s = '',
let s = '<' + nodeName,
propChildren,
html;

Expand All @@ -215,7 +221,7 @@ function _renderToString(vnode, context, opts, inner, isSvgMode, selectValue) {
continue;
}

if (name.match(/[\s\n\\/='"\0<>]/)) continue;
if (UNSAFE_NAME.test(name)) continue;

if (
!(opts && opts.allAttributes) &&
Expand Down Expand Up @@ -287,18 +293,19 @@ function _renderToString(vnode, context, opts, inner, isSvgMode, selectValue) {

// account for >1 multiline attribute
if (pretty) {
let sub = s.replace(/^\n\s*/, ' ');
let sub = s.replace(/\n\s*/, ' ');
if (sub !== s && !~sub.indexOf('\n')) s = sub;
else if (pretty && ~s.indexOf('\n')) s += '\n';
}

s = `<${nodeName}${s}>`;
if (UNSAFE_NAME.test(String(nodeName)))
s += '>';

if (UNSAFE_NAME.test(nodeName))
throw new Error(`${nodeName} is not a valid HTML tag name in ${s}`);

let isVoid =
VOID_ELEMENTS.test(String(nodeName)) ||
(opts.voidElements && opts.voidElements.test(String(nodeName)));
VOID_ELEMENTS.test(nodeName) ||
(opts.voidElements && opts.voidElements.test(nodeName));
let pieces = [];

let children;
Expand Down
15 changes: 5 additions & 10 deletions src/util.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,17 +1,12 @@
// DOM properties that should NOT have "px" added when numeric
export const IS_NON_DIMENSIONAL = /acit|ex(?:s|g|n|p|$)|rph|grid|ows|mnc|ntw|ine[ch]|zoo|^ord|^--/i;

const HTML_ENTITY_REG = /[&<>"]/g;
const tagsToReplace = {
'&': '&amp;',
'<': '&lt;',
'>': '&gt;',
'"': '&quot;'
};
const replaceTag = (tag) => tagsToReplace[tag] || tag;
export function encodeEntities(s) {
if (typeof s !== 'string') s = String(s);
return s.replace(HTML_ENTITY_REG, replaceTag);
return String(s)
Copy link
Member

@marvinhagemeister marvinhagemeister Mar 20, 2021 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Let's add a comment to summarize our findings from yesterdays quick benchmarking session and why we're going with the replace variant again.

Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I've always felt that this change was suspicious and could be the root cause of the performance issues I reported previously for versions after 5.1.2.

I plan to deploy a test release next Monday and roll back this part of the change separately from the 5.1.16 version of the code to see if there are still performance issues.

Copy link

@JimLiu JimLiu Mar 24, 2021 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

FYI https://jsben.ch/hR6XD
image

Copy link
Member Author

@developit developit Mar 25, 2021 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@JimLiu - that benchmark website produces statistically meaningless results. It's not open source (which is a problem), but I looked at the implementation and it's effectively running benchmarks in a tight loop: while(performance.now()-start < 5000) test(). This makes the order of benchmarks matter, and allows the JS VM to perform cross-benchmark optimizations that can only happen in the specific case of while(1) test() and never in real code.

The only current benchmarking website that produces statistically meaningful results is ESbench (disclaimer: I maintain it). The reason for this is because it uses the same Benchmark.js (the library that powered JSPerf, built by Matthias Bynens from the V8 team). Benchmark.js performs JIT warmup runs, encapsulates benchmarks in functions that prevent synthetic VM optimizations (like hoisting/inlining of benchmark code), and returns median values with standard deviation.

Here's the benchmarks we use for encodeEntities on ESBench:
https://esbench.com/bench/5f88af6cb4632100a7dcd414

Screen Shot 2021-03-25 at 11 45 36 AM

.replace(/&/g, '&amp;')
.replace(/</g, '&lt;')
.replace(/>/g, '&gt;')
.replace(/"/g, '&quot;');
}

export let indent = (s, char) =>
Expand Down