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I have a function getData(context) that holds a lot of information for a particular object.

I also have a function getPos() that gets a subset of that object. I do not wish to return the whole object.

I was hoping I would be able to do something like the function below.

// Example 1
getPos() {
    return { x, y } = getData(this); // Doesn't work
}

After looking at it, I completely understand why it doesn't work. So I changed it into 

// Example 2
getPos() {
    let { x, y } = getData(this);
    return { x, y };
}

And everything now works. But I was wondering if there was a more (one liner) way. I have the feeling I already have the most efficient way. And the only 1 liner way I can think of is to do

// Example 3
getPos() {
    return { x: getData(this).x, y: getData(this).y };
}

Which is just a little silly. In the future I will have similar functions, with more than just 2 properties, and with Example 2 I would need to list the properties twice. Once for the destructuring, and again for the new object construction. I guess I am more looking for readability and not having to use extra libraries. I have seen there are ways I could do this with Object.assign() but I believe this would return a clone of the whole getData() object and not just a subset.

WORMSS
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  • *"In the future I will have similar functions, with more than just 2 properties"*. So just create utility function: `return subset(getData(this), 'x', 'y')`. Where `function subset (obj, ...fields) { return fields.reduce((prev, curr) => { prev[curr] = obj[curr]; return prev }, {}) }` – dfsq Sep 20 '17 at 12:56

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