added TextAreaValueChangeList

[GavinJoyce]

Following up on #250 (comment)

/cc @chancancode

[rwjblue]

Can this section be safely moved to the updateAttribute method?

Something like:

export const TextAreaValueChangeList = {
  setAttribute(dom: DOMHelper, element: Element, attr: string, value: Opaque) {
    let textArea = <HTMLTextAreaElement>element;
    let normalizedValue = normalizeTextValue(value);
    let textNode = dom.createTextNode(normalizedValue);
    textArea.appendChild(textNode);
  },

  updateAttribute(dom: DOMHelper, element: Element, attr: string, value: Opaque) {
    let textArea = <HTMLTextAreaElement>element;
    let currentValue = textArea.value;
    if (currentValue !== normalizedValue) {
      textArea.value = normalizedValue;
    }
  }
};

Are there cases that ^ wouldn't work for?

[GavinJoyce]

It depends on how we want this to render when someValue is hello?

<textarea value={{someValue}}>why would someone put text here too?</textarea>

[GavinJoyce]

I just checked, with your proposed change the initial render would be:

<textarea>why would someone put text here too?hello</textarea>

then on updating someValue to "goodbye":

<textarea>goodbye</textarea>

It seems to be most consistent to ensure that the property value is used. The current PR has an initial render of:

<textarea>hello</textarea>

and after update:

<textarea>goodbye</textarea>

[rwjblue]

Well, technically <textarea> doesn't have an attribute for value. So actually having <textarea value={{someThing}}></textarea> seems wrong?

I was under the impression that writing a manual text area would look like:

<textarea>{{someValue}}</textarea>

Though I guess this also has issues, because now updates won't work properly?

[GavinJoyce]

It's a good point, the initial issue was to do with {{textarea value=foo}} where foo='', not <textarea value={{foo}} />.

Somewhere along the line I changed it to <textarea>, probably when trying to get a failing test in glimmer.

[GavinJoyce]

I've added a failing test in ember for the {{textarea value=someEmptyString}} case: emberjs/ember.js#14021

[GavinJoyce]

I've modified TextAreaValueChangeList as you suggested

[rwjblue]

@krisselden r+ in slack