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feat(removeDeprecatedAttrs): new removeDeprecatedAttrs plugin
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The new removeDeprecatedAttributes removes deprecated attributes from
the SVG document. For example, the "version" attribute on the "svg"
element is deprecated and not recommended as documented on MDN:

https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/version

> Deprecated: This feature is no longer recommended. Though some
> browsers might still support it, it may have already been removed from
> the relevant web standards, may be in the process of being dropped, or
> may only be kept for compatibility purposes. Avoid using it, and
> update existing code if possible; see the compatibility table at the
> bottom of this page to guide your decision. Be aware that this feature
> may cease to work at any time.

The document:

```
<svg version="1.1" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
  <rect x="10" y="10" width="80" height="80"/>
</svg>
```

Becomes:

```
<svg viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
  <rect x="10" y="10" width="80" height="80"/>
</svg>
```

The plugin has a concept of "safe" and "unsafe" deprecated attributes. A
safe attribute is on that, when removed, does not alter the rendering.
An example is the "version" attribute described above. An unsafe
attribute is one that does change the rendering. By default, the plugin
only removes the safe attributes. The param "removeUnsafe" can be used
to also remove the unsafe ones.

Deprecated attributes may also appear in the SVG stylesheet as a
selector. When this occurs, the attribute won't be removed from the
document to avoid additional rendering changes.

The "xml:lang" attribute is deprecated but also has a replacement,
"lang", so this attribute is treated as a special case and is safe when
its replacement exists.

The plugin is built for easy expansion as new deprecated attributes are
discovered or announced. Simply add to ones of the "deprecated" sets in
plugins/_collections.js.

Fixes #1701
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jdufresne committed Jan 4, 2024
1 parent 9e01769 commit 2b3909a
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27 changes: 27 additions & 0 deletions docs/03-plugins/remove-deprecated-attrs.mdx
Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
---
title: Remove Deprecated Attributes
svgo:
pluginId: removeDeprecatedAttrs
defaultPlugin: true
parameters:
removeAny:
description: By default, this plugin only removes safe deprecated attributes that do not change the rendered image. Enabling this will remove all deprecated attributes which may impact rendering.
type: boolean
default: false
---

Removes deprecated attributes from elements in the document.

This plugin does not remove attributes from the deprecated XLink namespace. To remove them, use the [Remove XLink](/docs/plugins/remove-xlink/) plugin.

## Usage

<PluginUsage />

## Demo

<PluginDemo />

## Implementation

- https://github.com/svg/svgo/blob/main/plugins/removeDeprecatedAttrs.js
2 changes: 2 additions & 0 deletions lib/builtin.js
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@ import * as prefixIds from '../plugins/prefixIds.js';
import * as removeAttributesBySelector from '../plugins/removeAttributesBySelector.js';
import * as removeAttrs from '../plugins/removeAttrs.js';
import * as removeComments from '../plugins/removeComments.js';
import * as removeDeprecatedAttrs from '../plugins/removeDeprecatedAttrs.js';
import * as removeDesc from '../plugins/removeDesc.js';
import * as removeDimensions from '../plugins/removeDimensions.js';
import * as removeDoctype from '../plugins/removeDoctype.js';
Expand Down Expand Up @@ -79,6 +80,7 @@ export const builtin = [
removeAttributesBySelector,
removeAttrs,
removeComments,
removeDeprecatedAttrs,
removeDesc,
removeDimensions,
removeDoctype,
Expand Down
102 changes: 102 additions & 0 deletions plugins/_collections.js
Original file line number Diff line number Diff line change
Expand Up @@ -375,11 +375,35 @@ export const attrsGroupsDefaults = {
},
};

/**
* @type {Record<string, { safe?: Set<string>, unsafe?: Set<string> }>}
* @see https://www.w3.org/TR/SVG11/intro.html#Definitions
*/
export const attrsGroupsDeprecated = {
animationAttributeTarget: { unsafe: new Set(['attributeType']) },
conditionalProcessing: { unsafe: new Set(['requiredFeatures']) },
core: { unsafe: new Set(['xml:base', 'xml:lang', 'xml:space']) },
presentation: {
unsafe: new Set([
'clip',
'color-profile',
'enable-background',
'glyph-orientation-horizontal',
'glyph-orientation-vertical',
'kerning',
]),
},
};

/**
* @type {Record<string, {
* attrsGroups: Set<string>,
* attrs?: Set<string>,
* defaults?: Record<string, string>,
* deprecated?: {
* safe?: Set<string>,
* unsafe?: Set<string>,
* },
* contentGroups?: Set<string>,
* content?: Set<string>,
* }>}
Expand Down Expand Up @@ -574,6 +598,7 @@ export const elems = {
name: 'sRGB',
'rendering-intent': 'auto',
},
deprecated: { unsafe: new Set(['name']) },
contentGroups: new Set(['descriptive']),
},
cursor: {
Expand Down Expand Up @@ -958,6 +983,7 @@ export const elems = {
width: '120%',
height: '120%',
},
deprecated: { unsafe: new Set(['filterRes']) },
contentGroups: new Set(['descriptive', 'filterPrimitive']),
content: new Set(['animate', 'set']),
},
Expand All @@ -978,6 +1004,15 @@ export const elems = {
'horiz-origin-x': '0',
'horiz-origin-y': '0',
},
deprecated: {
unsafe: new Set([
'horiz-origin-x',
'horiz-origin-y',
'vert-adv-y',
'vert-origin-x',
'vert-origin-y',
]),
},
contentGroups: new Set(['descriptive']),
content: new Set(['font-face', 'glyph', 'hkern', 'missing-glyph', 'vkern']),
},
Expand Down Expand Up @@ -1028,6 +1063,31 @@ export const elems = {
'panose-1': '0 0 0 0 0 0 0 0 0 0',
slope: '0',
},
deprecated: {
unsafe: new Set([
'accent-height',
'alphabetic',
'ascent',
'bbox',
'cap-height',
'descent',
'hanging',
'ideographic',
'mathematical',
'panose-1',
'slope',
'stemh',
'stemv',
'unicode-range',
'units-per-em',
'v-alphabetic',
'v-hanging',
'v-ideographic',
'v-mathematical',
'widths',
'x-height',
]),
},
contentGroups: new Set(['descriptive']),
content: new Set([
// TODO: "at most one 'font-face-src' element"
Expand All @@ -1038,10 +1098,12 @@ export const elems = {
'font-face-format': {
attrsGroups: new Set(['core']),
attrs: new Set(['string']),
deprecated: { unsafe: new Set(['string']) },
},
'font-face-name': {
attrsGroups: new Set(['core']),
attrs: new Set(['name']),
deprecated: { unsafe: new Set(['name']) },
},
'font-face-src': {
attrsGroups: new Set(['core']),
Expand Down Expand Up @@ -1134,6 +1196,18 @@ export const elems = {
defaults: {
'arabic-form': 'initial',
},
deprecated: {
unsafe: new Set([
'arabic-form',
'glyph-name',
'horiz-adv-x',
'orientation',
'unicode',
'vert-adv-y',
'vert-origin-x',
'vert-origin-y',
]),
},
contentGroups: new Set([
'animation',
'descriptive',
Expand Down Expand Up @@ -1173,6 +1247,14 @@ export const elems = {
'vert-origin-x',
'vert-origin-y',
]),
deprecated: {
unsafe: new Set([
'horiz-adv-x',
'vert-adv-y',
'vert-origin-x',
'vert-origin-y',
]),
},
contentGroups: new Set([
'animation',
'descriptive',
Expand Down Expand Up @@ -1236,6 +1318,7 @@ export const elems = {
hkern: {
attrsGroups: new Set(['core']),
attrs: new Set(['u1', 'g1', 'u2', 'g2', 'k']),
deprecated: { unsafe: new Set(['g1', 'g2', 'k', 'u1', 'u2']) },
},
image: {
attrsGroups: new Set([
Expand Down Expand Up @@ -1430,6 +1513,14 @@ export const elems = {
'vert-origin-x',
'vert-origin-y',
]),
deprecated: {
unsafe: new Set([
'horiz-adv-x',
'vert-adv-y',
'vert-origin-x',
'vert-origin-y',
]),
},
contentGroups: new Set([
'animation',
'descriptive',
Expand Down Expand Up @@ -1710,6 +1801,15 @@ export const elems = {
contentScriptType: 'application/ecmascript',
contentStyleType: 'text/css',
},
deprecated: {
safe: new Set(['version']),
unsafe: new Set([
'baseProfile',
'contentScriptType',
'contentStyleType',
'zoomAndPan',
]),
},
contentGroups: new Set([
'animation',
'descriptive',
Expand Down Expand Up @@ -1956,11 +2056,13 @@ export const elems = {
'viewTarget',
'zoomAndPan',
]),
deprecated: { unsafe: new Set(['viewTarget', 'zoomAndPan']) },
contentGroups: new Set(['descriptive']),
},
vkern: {
attrsGroups: new Set(['core']),
attrs: new Set(['u1', 'g1', 'u2', 'g2', 'k']),
deprecated: { unsafe: new Set(['g1', 'g2', 'k', 'u1', 'u2']) },
},
};

Expand Down
3 changes: 3 additions & 0 deletions plugins/plugins-types.d.ts
Original file line number Diff line number Diff line change
Expand Up @@ -143,6 +143,9 @@ type DefaultPlugins = {
removeComments: {
preservePatterns: Array<RegExp | string> | false;
};
removeDeprecatedAttrs: {
removeUnsafe?: boolean;
};
removeDesc: {
removeAny?: boolean;
};
Expand Down
2 changes: 2 additions & 0 deletions plugins/preset-default.js
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ import { createPreset } from '../lib/svgo/plugins.js';
import * as removeDoctype from './removeDoctype.js';
import * as removeXMLProcInst from './removeXMLProcInst.js';
import * as removeComments from './removeComments.js';
import * as removeDeprecatedAttrs from './removeDeprecatedAttrs.js';
import * as removeMetadata from './removeMetadata.js';
import * as removeEditorsNSData from './removeEditorsNSData.js';
import * as cleanupAttrs from './cleanupAttrs.js';
Expand Down Expand Up @@ -41,6 +42,7 @@ const presetDefault = createPreset({
removeDoctype,
removeXMLProcInst,
removeComments,
removeDeprecatedAttrs,
removeMetadata,
removeEditorsNSData,
cleanupAttrs,
Expand Down
120 changes: 120 additions & 0 deletions plugins/removeDeprecatedAttrs.js
Original file line number Diff line number Diff line change
@@ -0,0 +1,120 @@
import * as csswhat from 'css-what';
import { attrsGroupsDeprecated, elems } from './_collections.js';
import { collectStylesheet } from '../lib/style.js';

export const name = 'removeDeprecatedAttrs';
export const description = 'removes deprecated attributes';

/**
* @typedef {{ safe?: Set<string>; unsafe?: Set<string> }} DeprecatedAttrs
* @typedef {import('../lib/types.js').XastElement} XastElement
*/

/**
* @param {import('../lib/types.js').Stylesheet} stylesheet
* @returns {Set<string>}
*/
function extractAttributesInStylesheet(stylesheet) {
const attributesInStylesheet = new Set();

stylesheet.rules.forEach((rule) => {
const selectors = csswhat.parse(rule.selector);
selectors.forEach((subselector) => {
subselector.forEach((segment) => {
if (segment.type !== 'attribute') {
return;
}

attributesInStylesheet.add(segment.name);
});
});
});

return attributesInStylesheet;
}

/**
* @param {XastElement} node
* @param {DeprecatedAttrs | undefined} deprecatedAttrs
* @param {import('./plugins-types.js').DefaultPlugins['removeDeprecatedAttrs']} params
* @param {Set<string>} attributesInStylesheet
*/
function processAttributes(
node,
deprecatedAttrs,
params,
attributesInStylesheet,
) {
if (!deprecatedAttrs) {
return;
}

if (deprecatedAttrs.safe) {
deprecatedAttrs.safe.forEach((name) => {
if (attributesInStylesheet.has(name)) {
return;
}
delete node.attributes[name];
});
}

if (params.removeUnsafe && deprecatedAttrs.unsafe) {
deprecatedAttrs.unsafe.forEach((name) => {
if (attributesInStylesheet.has(name)) {
return;
}
delete node.attributes[name];
});
}
}

/**
* Remove deprecated attributes.
*
* @type {import('./plugins-types.js').Plugin<'removeDeprecatedAttrs'>}
*/
export function fn(root, params) {
const stylesheet = collectStylesheet(root);
const attributesInStylesheet = extractAttributesInStylesheet(stylesheet);

return {
element: {
enter: (node) => {
const elemConfig = elems[node.name];
if (!elemConfig) {
return;
}

// Special cases

// Removing deprecated xml:lang is safe when the lang attribute exists.
if (
elemConfig.attrsGroups.has('core') &&
node.attributes['xml:lang'] &&
!attributesInStylesheet.has('xml:lang') &&
node.attributes['lang']
) {
delete node.attributes['xml:lang'];
}

// General cases

elemConfig.attrsGroups.forEach((attrsGroup) => {
processAttributes(
node,
attrsGroupsDeprecated[attrsGroup],
params,
attributesInStylesheet,
);
});

processAttributes(
node,
elemConfig.deprecated,
params,
attributesInStylesheet,
);
},
},
};
}
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