Hyperscript Tagged Markup: JSX alternative using standard tagged templates, with compiler support.
import options by @drjayvee in https://github.com/developit/htm/pull/210
Full Changelog: https://github.com/developit/htm/compare/3.1.0...3.1.1
htm/preact package now re-exports useErrorBoundary (#180, thanks @artisonian!)<a:b c:d="e" />)Just a quick version bump due to v3.0.0 getting released without the built files 😅
HTM can now detect and cache static nodes (#132). A node is considered static when it or its children do not depend on any dynamic values injected into the template string.
In the following example the subtree rooted at <p class="a"> is static. The <p class="b"> is not static because its text contains a value injected into the template string. Also the root <div> is not static because one of its children is not static:
html`
<div>
<p class="a">
This is a <em>static</em> subtree.
</p>
<p class="b">
This is ${"not"}.
</p>
</div>
`;
When the template is evaluated for the first time HTM caches the <p class="a"> subtree created by the h function and reuses that value on subsequent evaluations.
For those familiar with @babel/plugin-transform-react-constant-elements it's kind of like that, though a bit less smart but done fully at runtime.
The standalone Preact bundle htm/preact/standalone was updated to Preact X (#125).
Preact hooks (included in the preact/hooks addon) were one of Preact X's marquee features. Pull request #134 by @zserge added Preact hooks as a part of the standalone bundle. Now you can import useState and friends directly like this:
import { html, render, useState } from 'https://unpkg.com/htm/preact/standalone.module.js';
The Babel plugin that compiles htm syntax to hyperscript, babel-plugin-htm, got smarter, thanks to PR #133 by @zaygraveyard! Adding import: 'preact' as an option to the plugin automatically adds import { h } from "preact"; to files that use HTM. So a file like this:
import { html } from "htm/preact";
html`<div id=hello>hello</div>`;
compiles to this:
import { h } from "preact";
import { html } from "htm/preact"; // <-- can now be tree-shaken away
h("div",{id:"hello"},"hello");
The option is highly configurable, so see the documentation for more examples.
As of version 3.0.0, HTM now requires Map (#132). This should not require a polyfill, since the Map functionality HTM relies on is supported in IE11 and all modern browsers.
Maintenance release: adds .mjs copies of the new .module.js dist files to avoid broken unpkg links (#113).
Mixed static + dynamic property values are back! (#93)
This was something that got lost during transition to HTM 2, but now it's making a comeback! Multiple joined static and dynamic values get concatenated together as strings. So this works now:
html`<a href="/pages/${id}" />`;
// ...or even:
html`<Route path=/${base}/users/me />`;
Support HTML-style comments (#84)
Another thing lost in the transition to HTM 2. Now everything between comment delimiters <!-- and --> gets ignored during parsing:
html`
<div>
<!-- Everything between comment delimiters
gets ignored, including <tags>,
newlines and ${"variables"} -->
</div>
`;
Convert JSX fragments in babel-plugin-transform-jsx-to-htm (#85, thanks @blikblum!)
babel-plugin-transform-jsx-to-htm now understands React.Fragment elements in the JSX input:
<React.Fragment>
<div>Foo</div>
<div>Bar</div>
</React.Fragment>
The plugin transforms fragments to htm expressions with multiple root elements - look how clean the output is:
html`<div>Foo</div><div>Bar</div>`;
Support for native Object Spread in babel-plugin-htm (#99)
Setting the plugin option useNativeSpread to true makes the transformed output use object spread syntax instead of Object.assign calls. If you're targeting modern browsers that support spread, this option can help reduce your bundle size!
// input:
html`<Link href="/1" ...${props} />`;
// output:
h(Link, { href: "/1", ...props });
babel-plugin-transform-jsx-to-htm's tag name handling closer to JSX (#92)babel-plugin-transform-jsx-to-htm (#98)babel-plugin-htm handles text (and other non-element) roots (#105)babel-plugin-transform-jsx-to-htm's package.json module field (#87, thanks @blikblum!)htm's peerDependencies to avoid warnings (#102)htm usage with integrations (#101, thanks @robdodson!)