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[next] deopt spreads in DOM #472

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b64e8bd
deopt spreads in DOM
titoBouzout Nov 2, 2025
e7c4f8b
de-duplicate attributes when not using spreads
titoBouzout Nov 4, 2025
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32 changes: 26 additions & 6 deletions packages/babel-plugin-jsx-dom-expressions/src/dom/element.js
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Original file line number Diff line number Diff line change
Expand Up @@ -297,6 +297,31 @@ function transformAttributes(path, results) {
);
//NOTE: can't be checked at compile time so add to compiled output
hasHydratableEvent = true;
} else {
/**
* Spreads already de-duplicate attributes.
*
* This handles the case when attributes are duplicated without the presence of a spread. Such:
* `<div style="duplicate1" style="duplicate2" />;`
*/
const seenAttributes = {};
const duplicates = [];
path
.get("openingElement")
.get("attributes")
.forEach(attr => {
const key = t.isJSXNamespacedName(attr.node.name)
? `${attr.node.name.namespace.name}:${attr.node.name.name.name}`
: attr.node.name.name;

if (!key.startsWith("use:") && key !== "ref" && seenAttributes[key]) {
duplicates.push(seenAttributes[key]);
}
seenAttributes[key] = attr;
});
for (const duplicate of duplicates) {
duplicate.remove();
}
}

/**
Expand Down Expand Up @@ -1171,12 +1196,7 @@ function processSpreads(path, attributes, { elem, isSVG, hasChildren, wrapCondit
: node.argument;

spreadArgs.push(isStatic ? t.objectExpression([t.spreadElement(s)]) : s);
} else if (
(firstSpread ||
(t.isJSXExpressionContainer(node.value) &&
isDynamic(attribute.get("value").get("expression"), { checkMember: true }))) &&
canNativeSpread(key, { checkNameSpaces: true })
) {
} else if (key && !key.startsWith("use:") && key !== "ref") {
const isContainer = t.isJSXExpressionContainer(node.value);
const dynamic =
isContainer && isDynamic(attribute.get("value").get("expression"), { checkMember: true });
Expand Down
2 changes: 2 additions & 0 deletions ...-plugin-jsx-dom-expressions/test/__dom_compatible_fixtures__/attributeExpressions/code.js
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Original file line number Diff line number Diff line change
Expand Up @@ -325,3 +325,5 @@ const template88 = (
{count()}
</button>
);

const template89 = <div style="duplicate1" style="duplicate2"/>
91 changes: 58 additions & 33 deletions ...lugin-jsx-dom-expressions/test/__dom_compatible_fixtures__/attributeExpressions/output.js
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Original file line number Diff line number Diff line change
Expand Up @@ -11,9 +11,7 @@ import { className as _$className } from "r-dom";
import { use as _$use } from "r-dom";
import { spread as _$spread } from "r-dom";
import { mergeProps as _$mergeProps } from "r-dom";
var _tmpl$ = /*#__PURE__*/ _$template(
`<div id="main"><h1 id="my-h1"><a href="/">Welcome</a></h1></div>`
),
var _tmpl$ = /*#__PURE__*/ _$template(`<div><h1><a href="/">Welcome</a></h1></div>`),
_tmpl$2 = /*#__PURE__*/ _$template(`<div><div></div><div> </div><div></div></div>`),
_tmpl$3 = /*#__PURE__*/ _$template(`<div foo></div>`),
_tmpl$4 = /*#__PURE__*/ _$template(`<div></div>`),
Expand All @@ -29,7 +27,7 @@ var _tmpl$ = /*#__PURE__*/ _$template(
_tmpl$14 = /*#__PURE__*/ _$template(`<div data="&quot;hi&quot;"data2="&quot;"></div>`),
_tmpl$15 = /*#__PURE__*/ _$template(`<a></a>`),
_tmpl$16 = /*#__PURE__*/ _$template(`<div><a></a></div>`),
_tmpl$17 = /*#__PURE__*/ _$template(`<div start="Hi">Hi</div>`),
_tmpl$17 = /*#__PURE__*/ _$template(`<div>Hi</div>`),
_tmpl$18 = /*#__PURE__*/ _$template(`<label><span>Input is </span><input><div></div></label>`),
_tmpl$19 = /*#__PURE__*/ _$template(
`<div class="class1 class2 class3 class4 class5 class6"random="random1 random2\n random3 random4"style="color:red;background-color:blue !important;border:1px solid black;font-size:12px"></div>`
Expand Down Expand Up @@ -72,7 +70,8 @@ var _tmpl$ = /*#__PURE__*/ _$template(
_tmpl$43 = /*#__PURE__*/ _$template(`<video poster="1.jpg"></video>`),
_tmpl$44 = /*#__PURE__*/ _$template(`<div><video poster="1.jpg"></video></div>`),
_tmpl$45 = /*#__PURE__*/ _$template(`<div><video></video></div>`),
_tmpl$46 = /*#__PURE__*/ _$template(`<button type="button"></button>`);
_tmpl$46 = /*#__PURE__*/ _$template(`<button type="button"></button>`),
_tmpl$47 = /*#__PURE__*/ _$template(`<div style="duplicate2"></div>`);
import * as styles from "./styles.module.css";
import { binding } from "somewhere";
function refFn() {}
Expand All @@ -86,41 +85,53 @@ const template = (() => {
_el$3 = _el$2.firstChild;
_$spread(
_el$,
_$mergeProps(results, {
class: {
selected: unknown
_$mergeProps(
{
id: "main"
},
style: {
color
results,
{
class: {
selected: unknown
},
style: {
color
}
}
}),
),
false,
true
);
_$spread(
_el$2,
_$mergeProps(results, {
foo: "",
disabled: "",
get title() {
return welcoming();
},
get style() {
return {
"background-color": color(),
"margin-right": "40px"
};
_$mergeProps(
{
id: id
},
get ["class"]() {
return [
"base",
{
dynamic: dynamic(),
selected
}
];
results,
{
foo: "",
disabled: "",
get title() {
return welcoming();
},
get style() {
return {
"background-color": color(),
"margin-right": "40px"
};
},
get ["class"]() {
return [
"base",
{
dynamic: dynamic(),
selected
}
];
}
}
}),
),
false,
true
);
Expand Down Expand Up @@ -385,15 +396,28 @@ const template25 = (() => {
})();
const template26 = (() => {
var _el$35 = _tmpl$17();
_$setAttribute(_el$35, "middle", middle);
_$spread(_el$35, spread, false, true);
_$spread(
_el$35,
_$mergeProps(
{
start: "Hi",
middle: middle
},
spread
),
false,
true
);
return _el$35;
})();
const template27 = (() => {
var _el$36 = _tmpl$17();
_$spread(
_el$36,
_$mergeProps(
{
start: "Hi"
},
first,
{
middle: middle
Expand Down Expand Up @@ -820,4 +844,5 @@ const template88 = (() => {
});
return _el$107;
})();
const template89 = _tmpl$47();
_$delegateEvents(["click", "input"]);
87 changes: 56 additions & 31 deletions ...ges/babel-plugin-jsx-dom-expressions/test/__dom_fixtures__/attributeExpressions/output.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ import { className as _$className } from "r-dom";
import { use as _$use } from "r-dom";
import { spread as _$spread } from "r-dom";
import { mergeProps as _$mergeProps } from "r-dom";
var _tmpl$ = /*#__PURE__*/ _$template(`<div id=main><h1 id=my-h1><a href=/>Welcome`),
var _tmpl$ = /*#__PURE__*/ _$template(`<div><h1><a href=/>Welcome`),
_tmpl$2 = /*#__PURE__*/ _$template(`<div><div></div><div> </div><div>`),
_tmpl$3 = /*#__PURE__*/ _$template(`<div foo>`),
_tmpl$4 = /*#__PURE__*/ _$template(`<div>`),
Expand All @@ -27,7 +27,7 @@ var _tmpl$ = /*#__PURE__*/ _$template(`<div id=main><h1 id=my-h1><a href=/>Welco
_tmpl$14 = /*#__PURE__*/ _$template(`<div data="&quot;hi&quot;"data2="&quot;">`),
_tmpl$15 = /*#__PURE__*/ _$template(`<a>`),
_tmpl$16 = /*#__PURE__*/ _$template(`<div><a>`),
_tmpl$17 = /*#__PURE__*/ _$template(`<div start=Hi>Hi`),
_tmpl$17 = /*#__PURE__*/ _$template(`<div>Hi`),
_tmpl$18 = /*#__PURE__*/ _$template(`<label><span>Input is </span><input><div>`),
_tmpl$19 = /*#__PURE__*/ _$template(
`<div class="class1 class2 class3 class4 class5 class6"random="random1 random2\n random3 random4"style="color:red;background-color:blue !important;border:1px solid black;font-size:12px">`
Expand Down Expand Up @@ -74,41 +74,53 @@ const template = (() => {
_el$3 = _el$2.firstChild;
_$spread(
_el$,
_$mergeProps(results, {
class: {
selected: unknown
_$mergeProps(
{
id: "main"
},
style: {
color
results,
{
class: {
selected: unknown
},
style: {
color
}
}
}),
),
false,
true
);
_$spread(
_el$2,
_$mergeProps(results, {
foo: "",
disabled: "",
get title() {
return welcoming();
},
get style() {
return {
"background-color": color(),
"margin-right": "40px"
};
_$mergeProps(
{
id: id
},
get ["class"]() {
return [
"base",
{
dynamic: dynamic(),
selected
}
];
results,
{
foo: "",
disabled: "",
get title() {
return welcoming();
},
get style() {
return {
"background-color": color(),
"margin-right": "40px"
};
},
get ["class"]() {
return [
"base",
{
dynamic: dynamic(),
selected
}
];
}
}
}),
),
false,
true
);
Expand Down Expand Up @@ -373,15 +385,28 @@ const template25 = (() => {
})();
const template26 = (() => {
var _el$35 = _tmpl$17();
_$setAttribute(_el$35, "middle", middle);
_$spread(_el$35, spread, false, true);
_$spread(
_el$35,
_$mergeProps(
{
start: "Hi",
middle: middle
},
spread
),
false,
true
);
return _el$35;
})();
const template27 = (() => {
var _el$36 = _tmpl$17();
_$spread(
_el$36,
_$mergeProps(
{
start: "Hi"
},
first,
{
middle: middle
Expand Down Expand Up @@ -808,4 +833,4 @@ const template88 = (() => {
});
return _el$107;
})();
_$delegateEvents(["click", "input"]);
_$delegateEvents(["click", "input"]);
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