add a simple observer readme section #23
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| @@ -126,6 +126,14 @@ class TestElement extends Polymer.Element { | |||
| @property() | |||
| bar: string = 'yes'; | |||
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| // @observe does not support simple observers, | |||
| // you can already do that via a normal property | |||
| @property({ observer: TestElement.prototype.onBazChanged }) | |||
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This depends on #18 right? That requires that observer is a string, which is also how Polymer normally works (AFAIK you can't pass a function reference in the normal Polymer block, or at least that's an undocumented feature if you can).
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It depends on #18 (PropertyOptions has no observer in master). so yes we need to change it to string|((val: any, old: any) => void) or something i suppose, maybe in this PR?
You can pass a function reference as of very recently due to Polymer/polymer#4574. it doesn't seem to be documented well, if at all.
its probably best we recommend this, though, as its a little stronger typed than the string version.
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It depends on #18 (PropertyOptions has no observer in master). so yes we need to change it to string|((val: any, old: any) => void) or something i suppose, maybe in this PR?
You can pass a function reference as of very recently due to Polymer/polymer#4574. it doesn't seem to be documented well, if at all.
Ah, I missed that change. Yes, would be great to also add the new signature to this PR, string|((val: any, old: any) => void) seems right.
BTW we should also update https://github.com/Polymer/polymer/blob/master/types/extra-types.d.ts to match https://github.com/Polymer/polymer/blob/master/externs/polymer-externs.js#L24, maybe in Polymer/polymer#5000?
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yup can do. i added the observer definition here too now.
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Updated the readme a tiny bit to explain how to do a simple observer (a property's observer).
would typescript complain about this? doesn't seem to locally but wasn't sure about accessing a private method on the prototype.