On May 28, 2012, at 1:23 PM, Erik Arvidsson wrote:
> On Mon, May 28, 2012 at 12:19 PM, Nicholas C. Zakas
> <[email protected]> wrote:
>> Is it intentional that the first example uses colons between the property
>> and value while all others use the equals sign?
>
> Yes this is intentional. We discussed this a bit at the F2F meeting
> and we came up with the proposal to use = for [[Put]] and : for
> [[DefineOwnProperty]]. Having a way to do [[Put]] is important because
> it is common to want to trigger setters.
At added a clarification of this to the strawman....
>
> For example:
>
> class Monster {
> set health(value) {
> this.barColor = value < 10 ? 'red' : 'green';
> this._health = value;
> }
> }
>
> class GiantSpider extends Monster {
> constructor() {
> this.{
> health = 100
> }
> }
> }
>
> If you use .{health: 100} then the setter would not be invoked and the
> object would not be in a correct state. This example might be a bit
> contrived but using [[DefineOwnProperty]] is not the right answer in a
> lot of cases.
>
This is especially important for setting values of DOM node properties which
are generally implemented as accessor properties (ie, getters/setters). That
is why I used (thanks to dherman) a DOM element in most of the example that use
+.
Allen
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