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Fix some css issues with :hover and rewrite max-device-width (rrweb-i…
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…o#1431)

* We weren't recursing into media queries (or @supports etc.) to rewrite hover pseudoclasses

* The early return meant that the stylesWithHoverClass cache wasn't being populated if there were no hover selectors on the stylesheet

 - not committing the test, but modifying the existing 'add a hover class to a previously processed css string' as follows shows the problem:

--- a/packages/rrweb-snapshot/test/rebuild.test.ts
+++ b/packages/rrweb-snapshot/test/rebuild.test.ts
@@ -151,6 +185,7 @@ describe('rebuild', function () {
         path.resolve(__dirname, './css/benchmark.css'),
         'utf8',
       );
+      cssText = cssText.replace(/:hover/g, '');

       const start = process.hrtime();
       addHoverClass(cssText, cache);

* Replace `min-device-width` and similar with `min-width` as the former looks out at the browser viewport whereas we need it to look at the replayer iframe viewport

* Add some tests to show how the hover replacement works against selector lists. I believe these were failing in a previous version of rrweb as I had some local patches that no longer seem to be needed to handle these cases

* Update name of function to reflect that 'addHoverClass' does more than just :hover. I believe this function is only exported for the purposes of use in the tests

* Apply formatting changes

* Create rotten-spies-enjoy.md

* Apply formatting changes

* Add correct typing on `getSelectors`

* Refactor CSS interfaces to include optional rules

* Change `rules` to be non optional

---------

Co-authored-by: eoghanmurray <[email protected]>
Co-authored-by: Justin Halsall <[email protected]>
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3 people authored Mar 26, 2024
1 parent e607e83 commit a7c33f2
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7 changes: 7 additions & 0 deletions .changeset/rotten-spies-enjoy.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
---
'rrweb-snapshot': patch
'rrweb': patch
---

Ensure :hover works on replayer, even if a rule is behind a media query
Respect the intent behind max-device-width and min-device-width media queries so that their effects are apparent in the replayer context
30 changes: 12 additions & 18 deletions packages/rrweb-snapshot/src/css.ts
Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,11 @@ export interface Node {
};
}

export interface NodeWithRules extends Node {
/** Array of nodes with the types rule, comment and any of the at-rule types. */
rules: Array<Rule | Comment | AtRule>;
}

export interface Rule extends Node {
/** The list of selectors of the rule, split on commas. Each selector is trimmed from whitespace and comments. */
selectors?: string[];
Expand Down Expand Up @@ -98,13 +103,11 @@ export interface CustomMedia extends Node {
/**
* The @document at-rule.
*/
export interface Document extends Node {
export interface Document extends NodeWithRules {
/** The part following @document. */
document?: string;
/** The vendor prefix in @document, or undefined if there is none. */
vendor?: string;
/** Array of nodes with the types rule, comment and any of the at-rule types. */
rules?: Array<Rule | Comment | AtRule>;
}

/**
Expand All @@ -118,10 +121,7 @@ export interface FontFace extends Node {
/**
* The @host at-rule.
*/
export interface Host extends Node {
/** Array of nodes with the types rule, comment and any of the at-rule types. */
rules?: Array<Rule | Comment | AtRule>;
}
export type Host = NodeWithRules;

/**
* The @import at-rule.
Expand Down Expand Up @@ -153,11 +153,9 @@ export interface KeyFrame extends Node {
/**
* The @media at-rule.
*/
export interface Media extends Node {
export interface Media extends NodeWithRules {
/** The part following @media. */
media?: string;
/** Array of nodes with the types rule, comment and any of the at-rule types. */
rules?: Array<Rule | Comment | AtRule>;
}

/**
Expand All @@ -181,11 +179,9 @@ export interface Page extends Node {
/**
* The @supports at-rule.
*/
export interface Supports extends Node {
export interface Supports extends NodeWithRules {
/** The part following @supports. */
supports?: string;
/** Array of nodes with the types rule, comment and any of the at-rule types. */
rules?: Array<Rule | Comment | AtRule>;
}

/** All at-rules. */
Expand All @@ -205,10 +201,8 @@ export type AtRule =
/**
* A collection of rules
*/
export interface StyleRules {
export interface StyleRules extends NodeWithRules {
source?: string;
/** Array of nodes with the types rule, comment and any of the at-rule types. */
rules: Array<Rule | Comment | AtRule>;
/** Array of Errors. Errors collected during parsing when option silent is true. */
parsingErrors?: ParserError[];
}
Expand All @@ -224,7 +218,7 @@ export interface Stylesheet extends Node {
// https://github.com/visionmedia/css-parse/pull/49#issuecomment-30088027
const commentre = /\/\*[^*]*\*+([^/*][^*]*\*+)*\//g;

export function parse(css: string, options: ParserOptions = {}) {
export function parse(css: string, options: ParserOptions = {}): Stylesheet {
/**
* Positional.
*/
Expand Down Expand Up @@ -882,7 +876,7 @@ function trim(str: string) {
* Adds non-enumerable parent node reference to each node.
*/

function addParent(obj: Stylesheet, parent?: Stylesheet) {
function addParent(obj: Stylesheet, parent?: Stylesheet): Stylesheet {
const isNode = obj && typeof obj.type === 'string';
const childParent = isNode ? obj : parent;

Expand Down
4 changes: 2 additions & 2 deletions packages/rrweb-snapshot/src/index.ts
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ import snapshot, {
} from './snapshot';
import rebuild, {
buildNodeWithSN,
addHoverClass,
adaptCssForReplay,
createCache,
} from './rebuild';
export * from './types';
Expand All @@ -22,7 +22,7 @@ export {
serializeNodeWithId,
rebuild,
buildNodeWithSN,
addHoverClass,
adaptCssForReplay,
createCache,
transformAttribute,
ignoreAttribute,
Expand Down
80 changes: 54 additions & 26 deletions packages/rrweb-snapshot/src/rebuild.ts
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
import { parse } from './css';
import { Rule, Media, NodeWithRules, parse } from './css';
import {
serializedNodeWithId,
NodeType,
Expand Down Expand Up @@ -62,9 +62,11 @@ function escapeRegExp(str: string) {
return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
}

const MEDIA_SELECTOR = /(max|min)-device-(width|height)/;
const MEDIA_SELECTOR_GLOBAL = new RegExp(MEDIA_SELECTOR.source, 'g');
const HOVER_SELECTOR = /([^\\]):hover/;
const HOVER_SELECTOR_GLOBAL = new RegExp(HOVER_SELECTOR.source, 'g');
export function addHoverClass(cssText: string, cache: BuildCache): string {
export function adaptCssForReplay(cssText: string, cache: BuildCache): string {
const cachedStyle = cache?.stylesWithHoverClass.get(cssText);
if (cachedStyle) return cachedStyle;

Expand All @@ -77,35 +79,61 @@ export function addHoverClass(cssText: string, cache: BuildCache): string {
}

const selectors: string[] = [];
ast.stylesheet.rules.forEach((rule) => {
if ('selectors' in rule) {
(rule.selectors || []).forEach((selector: string) => {
const medias: string[] = [];
function getSelectors(rule: Rule | Media | NodeWithRules) {
if ('selectors' in rule && rule.selectors) {
rule.selectors.forEach((selector: string) => {
if (HOVER_SELECTOR.test(selector)) {
selectors.push(selector);
}
});
}
});

if (selectors.length === 0) {
return cssText;
if ('media' in rule && rule.media && MEDIA_SELECTOR.test(rule.media)) {
medias.push(rule.media);
}
if ('rules' in rule && rule.rules) {
rule.rules.forEach(getSelectors);
}
}
getSelectors(ast.stylesheet);

const selectorMatcher = new RegExp(
selectors
.filter((selector, index) => selectors.indexOf(selector) === index)
.sort((a, b) => b.length - a.length)
.map((selector) => {
return escapeRegExp(selector);
})
.join('|'),
'g',
);

const result = cssText.replace(selectorMatcher, (selector) => {
const newSelector = selector.replace(HOVER_SELECTOR_GLOBAL, '$1.\\:hover');
return `${selector}, ${newSelector}`;
});
let result = cssText;
if (selectors.length > 0) {
const selectorMatcher = new RegExp(
selectors
.filter((selector, index) => selectors.indexOf(selector) === index)
.sort((a, b) => b.length - a.length)
.map((selector) => {
return escapeRegExp(selector);
})
.join('|'),
'g',
);
result = result.replace(selectorMatcher, (selector) => {
const newSelector = selector.replace(
HOVER_SELECTOR_GLOBAL,
'$1.\\:hover',
);
return `${selector}, ${newSelector}`;
});
}
if (medias.length > 0) {
const mediaMatcher = new RegExp(
medias
.filter((media, index) => medias.indexOf(media) === index)
.sort((a, b) => b.length - a.length)
.map((media) => {
return escapeRegExp(media);
})
.join('|'),
'g',
);
result = result.replace(mediaMatcher, (media) => {
// not attempting to maintain min-device-width along with min-width
// (it's non standard)
return media.replace(MEDIA_SELECTOR_GLOBAL, '$1-$2');
});
}
cache?.stylesWithHoverClass.set(cssText, result);
return result;
}
Expand Down Expand Up @@ -196,7 +224,7 @@ function buildNode(
const isTextarea = tagName === 'textarea' && name === 'value';
const isRemoteOrDynamicCss = tagName === 'style' && name === '_cssText';
if (isRemoteOrDynamicCss && hackCss && typeof value === 'string') {
value = addHoverClass(value, cache);
value = adaptCssForReplay(value, cache);
}
if ((isTextarea || isRemoteOrDynamicCss) && typeof value === 'string') {
node.appendChild(doc.createTextNode(value));
Expand Down Expand Up @@ -341,7 +369,7 @@ function buildNode(
case NodeType.Text:
return doc.createTextNode(
n.isStyle && hackCss
? addHoverClass(n.textContent, cache)
? adaptCssForReplay(n.textContent, cache)
: n.textContent,
);
case NodeType.CDATA:
Expand Down
69 changes: 58 additions & 11 deletions packages/rrweb-snapshot/test/rebuild.test.ts
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,11 @@
*/
import * as fs from 'fs';
import * as path from 'path';
import { addHoverClass, buildNodeWithSN, createCache } from '../src/rebuild';
import {
adaptCssForReplay,
buildNodeWithSN,
createCache,
} from '../src/rebuild';
import { NodeType } from '../src/types';
import { createMirror, Mirror } from '../src/utils';

Expand Down Expand Up @@ -81,47 +85,90 @@ describe('rebuild', function () {
describe('add hover class to hover selector related rules', function () {
it('will do nothing to css text without :hover', () => {
const cssText = 'body { color: white }';
expect(addHoverClass(cssText, cache)).toEqual(cssText);
expect(adaptCssForReplay(cssText, cache)).toEqual(cssText);
});

it('can add hover class to css text', () => {
const cssText = '.a:hover { color: white }';
expect(addHoverClass(cssText, cache)).toEqual(
expect(adaptCssForReplay(cssText, cache)).toEqual(
'.a:hover, .a.\\:hover { color: white }',
);
});

it('can correctly add hover when in middle of selector', () => {
const cssText = 'ul li a:hover img { color: white }';
expect(adaptCssForReplay(cssText, cache)).toEqual(
'ul li a:hover img, ul li a.\\:hover img { color: white }',
);
});

it('can correctly add hover on multiline selector', () => {
const cssText = `ul li.specified a:hover img,
ul li.multiline
b:hover
img,
ul li.specified c:hover img {
color: white
}`;
expect(adaptCssForReplay(cssText, cache)).toEqual(
`ul li.specified a:hover img, ul li.specified a.\\:hover img,
ul li.multiline
b:hover
img, ul li.multiline
b.\\:hover
img,
ul li.specified c:hover img, ul li.specified c.\\:hover img {
color: white
}`,
);
});

it('can add hover class within media query', () => {
const cssText = '@media screen { .m:hover { color: white } }';
expect(adaptCssForReplay(cssText, cache)).toEqual(
'@media screen { .m:hover, .m.\\:hover { color: white } }',
);
});

it('can add hover class when there is multi selector', () => {
const cssText = '.a, .b:hover, .c { color: white }';
expect(addHoverClass(cssText, cache)).toEqual(
expect(adaptCssForReplay(cssText, cache)).toEqual(
'.a, .b:hover, .b.\\:hover, .c { color: white }',
);
});

it('can add hover class when there is a multi selector with the same prefix', () => {
const cssText = '.a:hover, .a:hover::after { color: white }';
expect(addHoverClass(cssText, cache)).toEqual(
expect(adaptCssForReplay(cssText, cache)).toEqual(
'.a:hover, .a.\\:hover, .a:hover::after, .a.\\:hover::after { color: white }',
);
});

it('can add hover class when :hover is not the end of selector', () => {
const cssText = 'div:hover::after { color: white }';
expect(addHoverClass(cssText, cache)).toEqual(
expect(adaptCssForReplay(cssText, cache)).toEqual(
'div:hover::after, div.\\:hover::after { color: white }',
);
});

it('can add hover class when the selector has multi :hover', () => {
const cssText = 'a:hover b:hover { color: white }';
expect(addHoverClass(cssText, cache)).toEqual(
expect(adaptCssForReplay(cssText, cache)).toEqual(
'a:hover b:hover, a.\\:hover b.\\:hover { color: white }',
);
});

it('will ignore :hover in css value', () => {
const cssText = '.a::after { content: ":hover" }';
expect(addHoverClass(cssText, cache)).toEqual(cssText);
expect(adaptCssForReplay(cssText, cache)).toEqual(cssText);
});

it('can adapt media rules to replay context', () => {
const cssText =
'@media only screen and (min-device-width : 1200px) { .a { width: 10px; }}';
expect(adaptCssForReplay(cssText, cache)).toEqual(
'@media only screen and (min-width : 1200px) { .a { width: 10px; }}',
);
});

// this benchmark is unreliable when run in parallel with other tests
Expand All @@ -131,7 +178,7 @@ describe('rebuild', function () {
'utf8',
);
const start = process.hrtime();
addHoverClass(cssText, cache);
adaptCssForReplay(cssText, cache);
const end = process.hrtime(start);
const duration = getDuration(end);
expect(duration).toBeLessThan(100);
Expand All @@ -146,11 +193,11 @@ describe('rebuild', function () {
);

const start = process.hrtime();
addHoverClass(cssText, cache);
adaptCssForReplay(cssText, cache);
const end = process.hrtime(start);

const cachedStart = process.hrtime();
addHoverClass(cssText, cache);
adaptCssForReplay(cssText, cache);
const cachedEnd = process.hrtime(cachedStart);

expect(getDuration(cachedEnd) * factor).toBeLessThan(getDuration(end));
Expand Down

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