{"action":"opened","issue":{"url":"https://api.github.com/repos/aurelia/framework/issues/251","labels_url":"https://api.github.com/repos/aurelia/framework/issues/251/labels{/name}","comments_url":"https://api.github.com/repos/aurelia/framework/issues/251/comments","events_url":"https://api.github.com/repos/aurelia/framework/issues/251/events","html_url":"https://github.com/aurelia/framework/issues/251","id":118709054,"number":251,"title":"Map.delete() and Map.delete() produce TypeError in aurelia-task-queue","user":{"login":"nnscr","id":2816344,"avatar_url":"https://avatars.githubusercontent.com/u/2816344?v=3","gravatar_id":"","url":"https://api.github.com/users/nnscr","html_url":"https://github.com/nnscr","followers_url":"https://api.github.com/users/nnscr/followers","following_url":"https://api.github.com/users/nnscr/following{/other_user}","gists_url":"https://api.github.com/users/nnscr/gists{/gist_id}","starred_url":"https://api.github.com/users/nnscr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/nnscr/subscriptions","organizations_url":"https://api.github.com/users/nnscr/orgs","repos_url":"https://api.github.com/users/nnscr/repos","events_url":"https://api.github.com/users/nnscr/events{/privacy}","received_events_url":"https://api.github.com/users/nnscr/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-11-24T21:40:54Z","updated_at":"2015-11-24T21:40:54Z","closed_at":null,"body":"Hey,\r\n\r\nfirst off: thanks for your great work, Aurelia is really lovely!\r\n\r\nI think I've found a bug in the current beta regarding Maps throwing this error:\r\nTypeError: Cannot read property 'firstChild' of undefined in aurelia-task-queue.js:40\r\n\r\nIf you bind a map like this:\r\n```html\r\n<li repeat.for=\"[k, v] of map\">\r\n  ${k}: ${v}\r\n</li>\r\n```\r\nYou can add elements using `set()`, which works the first time. If the key already exists, an error is thrown. The same error is thrown when you call `delete()`. `clear()` works as expected.\r\n\r\nI have prepared a Plunker where you can see what I mean. The issue did not occur in earlier versions (tested on 0.19, don't know about others).\r\n\r\nhttp://plnkr.co/edit/a3LGHJ0Llvh3e8JLdpRp?p=preview\r\n"}}