Angular2 with Typescript simple example with local variables

Question

I am trying to build a little app with Angular2. I want to use local variables, like it is explained here:

https://angular.io/docs/ts/latest/guide/user-input.html

<input #myname (keyup)>
<p>{{myname.value}}</p>

But it doesn't work as expected. If i press a key on the focused input field, the text in the p-tag should be updated. But all i get is an Exception:

EXCEPTION: TypeError: rec[(rec.length - 1)] is undefined

If i do something like this it will work, even if the foo method exists or not:

<input #myname (keyup)="foo()">
<p>{{myname.value}}</p>

I followed exactly the instructions on the page and i don't have any custom code.

when you use the (event) notation you must provide the function to be called .. The examples in the angular.io site are not up to date ( they use 2.0.0-alpha.37 .. the current version is alpha39 ) — Mourad Zouabi
– Mourad Zouabi, Commented Oct 8, 2015 at 20:05

Mark Rajcok · Accepted Answer · 2015-11-15 00:45:36Z

2

It looks like the docs have been updated:

<input #box (keyup)="0">

... an Event Binding requires a template expression to evaluate when the event fires. Many things qualify as expressions, none simpler than a one-character literal like the number zero. That's all it takes to keep Angular happy.

answered Nov 15, 2015 at 0:45

Mark Rajcok

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