mirror of
https://github.com/zebrajr/react.git
synced 2026-01-15 12:15:22 +00:00
978fae4b4f
This PR is now based on #26256 The original matching function for `hydrateHoistable` some challenging time complexity since we built up the list of matchable nodes for each link of that type and then had to check to exclusion. This new implementation aims to improve the complexity For hoisted title tags we match the first title if it is valid (not in SVG context and does not have `itemprop`, the two ways you opt out of hoisting when rendering titles). This path is much faster than others and we use it because valid Documents only have 1 title anyway and if we did have a mismatch the rendered title still ends up as the Document.title so there is no functional degradation for misses. For hoisted link and meta tags we track all potentially hydratable Elements of this type in a cache per Document. The cache is refreshed once each commit if and only if there is a title or meta hoistable hydrating. The caches are partitioned by a natural key for each type (href for link and content for meta). Then secondary attributes are checked to see if the potential match is matchable. For link we check `rel`, `title`, and `crossorigin`. These should provide enough entropy that we never have collisions except is contrived cases and even then it should not affect functionality of the page. This should also be tolerant of links being injected in arbitrary places in the Document by 3rd party scripts and browser extensions For meta we check `name`, `property`, `http-equiv`, and `charset`. These should provide enough entropy that we don't have meaningful collisions. It is concievable with og tags that there may be true duplciates `<meta property="og:image:size:height" content="100" />` but even if we did bind to the wrong instance meta tags are typically only read from SSR by bots and rarely inserted by 3rd parties so an adverse functional outcome is not expected.
The error code system substitutes React's error messages with error IDs to provide a better debugging support in production. Check out the blog post here.
codes.jsoncontains the mapping from IDs to error messages. This file is generated by the Gulp plugin and is used by both the Babel plugin and the error decoder page in our documentation. This file is append-only, which means an existing code in the file will never be changed/removed.extract-errors.jsis an node script that traverses our codebase and updatescodes.json. You can test it by runningyarn extract-errors. It works by crawling the build artifacts directory, so you need to have either run the build script or downloaded pre-built artifacts (e.g. withyarn download build). It works with partial builds, too.transform-error-messagesis a Babel pass that rewrites error messages to IDs for a production (minified) build.