{"action":"created","issue":{"url":"https://api.github.com/repos/tc39/ecma262/issues/262","labels_url":"https://api.github.com/repos/tc39/ecma262/issues/262/labels{/name}","comments_url":"https://api.github.com/repos/tc39/ecma262/issues/262/comments","events_url":"https://api.github.com/repos/tc39/ecma262/issues/262/events","html_url":"https://github.com/tc39/ecma262/issues/262","id":122600427,"number":262,"title":"Feature testing no longer possible with RegExp.prototype.sticky","user":{"login":"littledan","id":189835,"avatar_url":"https://avatars.githubusercontent.com/u/189835?v=3","gravatar_id":"","url":"https://api.github.com/users/littledan","html_url":"https://github.com/littledan","followers_url":"https://api.github.com/users/littledan/followers","following_url":"https://api.github.com/users/littledan/following{/other_user}","gists_url":"https://api.github.com/users/littledan/gists{/gist_id}","starred_url":"https://api.github.com/users/littledan/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/littledan/subscriptions","organizations_url":"https://api.github.com/users/littledan/orgs","repos_url":"https://api.github.com/users/littledan/repos","events_url":"https://api.github.com/users/littledan/events{/privacy}","received_events_url":"https://api.github.com/users/littledan/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":12,"created_at":"2015-12-16T21:02:09Z","updated_at":"2015-12-17T19:41:34Z","closed_at":"2015-12-17T19:41:34Z","body":"Some websites check for whether the JavaScript implementation supports the 'sticky' flag by reading RegExp.prototype.sticky. Under ES2015, this throws a TypeError because RegExp.prototype is not a RegExp.\r\n\r\nhttps://bugs.chromium.org/p/v8/issues/detail?id=4617#c9\r\n\r\nWhat if we make these flag accessors a little more tolerant? If `this` does not have a [[RegExpMatcher]] internal slot, how about returning `false`? As it stands, this is blocking us from shipping sticky RegExps."},"comment":{"url":"https://api.github.com/repos/tc39/ecma262/issues/comments/165560026","html_url":"https://github.com/tc39/ecma262/issues/262#issuecomment-165560026","issue_url":"https://api.github.com/repos/tc39/ecma262/issues/262","id":165560026,"user":{"login":"allenwb","id":505435,"avatar_url":"https://avatars.githubusercontent.com/u/505435?v=3","gravatar_id":"","url":"https://api.github.com/users/allenwb","html_url":"https://github.com/allenwb","followers_url":"https://api.github.com/users/allenwb/followers","following_url":"https://api.github.com/users/allenwb/following{/other_user}","gists_url":"https://api.github.com/users/allenwb/gists{/gist_id}","starred_url":"https://api.github.com/users/allenwb/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/allenwb/subscriptions","organizations_url":"https://api.github.com/users/allenwb/orgs","repos_url":"https://api.github.com/users/allenwb/repos","events_url":"https://api.github.com/users/allenwb/events{/privacy}","received_events_url":"https://api.github.com/users/allenwb/received_events","type":"User","site_admin":false},"created_at":"2015-12-17T19:41:34Z","updated_at":"2015-12-17T19:41:34Z","body":"So the test made by XRegExp must be some thing like:\r\n ```js\r\nvar supportsSticky = RegExp.prototype.sticky===false;\r\n```\r\nIn other words, must be explicitly check for **false** rather than a falsy value.\r\n\r\nNow, let's think about this a little deeper.\r\n\r\nPrior to ES6,  the sticky flag was only a feature of "}}