What's the meaning of const {a,b} = await foo();

Question

I'm trying to understand this alexa skill but I've never seen this:

const {
      playbackInfo,
      playbackSetting,
    } = await handlerInput.attributesManager.getPersistentAttributes();

You can find on line 48 here. Also at line 42 is not clear. What's the meaning when I see something like const {a,b} = await foo(); or const {a,b} = foo; I always seen const = something. I couldn't find it in the new ES6 features.

Possible duplicate of [Javascript object bracket notation ({ Navigation } =) on left side of assign](https://stackoverflow.com/questions/26999820/javascript-object-bracket-notation-navigation-on-left-side-of-assign) as listed on [this reference question](https://stackoverflow.com/questions/9549780/what-does-this-symbol-mean-in-javascript). — IMSoP, Dec 14 '18 at 15:01
https://medium.com/dailyjs/asynchronous-adventures-in-javascript-async-await-bd2e62f37ffd — Josh Adams, Dec 14 '18 at 15:02

score 4 · Accepted Answer · answered Dec 14 '18 at 15:02

4

1) handlerInput.attributesManager.getPersistentAttributes() returns a promise.

2) await waits for the promise to be resolved

3) const { a, b } deconstructs the object that is returned when the promise is resolved.

answered Dec 14 '18 at 15:02

Andy

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That's what I was looking for, the destructuring assignment. I don't know why I didn't find it before asking. My bad. – Mattia Dec 14 '18 at 15:15

What's the meaning of const {a,b} = await foo();

1 Answers1