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Spec https://github.com/tc39/proposal-regexp-lookbehind (stage 3 proposal) Summary Lookarounds are zero-width assertions that match a string without consuming anything. ECMAScript has lookahead assertions that does this in forward direction, but the language is missing a way to do this backward which the lookbehind assertions provide. With lookbehind assertions, one can make sure that a pattern is or isn’t preceded by another, e.g. matching a dollar amount without capturing the dollar sign. Link to “Intent to Implement” blink-dev discussion There was none. Note that since this is a V8/JS feature, this post is just an FYI to blink-dev — no signoff from Blink API owners is required. Is this feature supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes. Demo link Examples can be found here: - https://mathiasbynens.be/notes/es-regexp-proposals#lookbehinds - https://developers.google.com/web/updates/2017/07/upcoming-regexp-features#lookbehind_assertions Interoperability and Compatibility Risk Low; this feature gives behavior to something which was previously a syntax error. Edge/Chakra: public support; tracking issue: https://github.com/Microsoft/ChakraCore/issues/3448 Firefox/SpiderMonkey: no signals; tracking issue: https://bugzilla.mozilla.org/show_bug.cgi?id=1225665 Safari/JavaScriptCore: no signals; tracking issue: https://bugs.webkit.org/show_bug.cgi?id=174931 Web developers: positive signals Is this feature fully tested? Yes. In addition to V8’s own tests <https://github.com/v8/v8/blob/master/test/mjsunit/harmony/regexp-lookbehind.js>, Test262 includes tests for this feature <https://github.com/tc39/test262/tree/master/test/built-ins/RegExp/lookBehind> . OWP launch tracking bug https://bugs.chromium.org/p/v8/issues/detail?id=4545 Entry on the feature dashboard <http://www.chromestatus.com/> https://www.chromestatus.com/feature/5668726032564224 -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
