meta data: get property owners

[RebeccaStevens]

Would it be possible to get some more meta data? Assuming a property value should be set, based on values from other properties. It would be nice to not only get the property values and the property name but also be able to get the property owners.

Example:

const x = {a: 1, isBadObject: true};
const y = {a: 2, isBadObject: false};

...

mergeOthers: (values, utils, meta) => {
    const { key } = meta;
    if (key === "isBadObject") {
        return false;
    }        
    if (key === "a") {
        const owners = meta.getOwners();
        let result = 0;
        for (let i = 0; i < values.length; i++) {
            if (!owners[i].isBadObject) {
                result += values[i];
            }
            else {
                // Skip bad object.
            }
        }
        return result;
    }
    return; // Trigger default merging (see my above post)
}

I used a function call to get the owners, because otherwise it might not be good for performance if meta would always provide the owners array out-of-the-box, instead of only providing it when commanded to do so.

Via metaDataUpdater a client could also provide the full ancestor chain to the custom merger, if for some reason the client needs that info. Note: In that ancestor chain also arrays could occur (not just plain objects). So when merging something like {arr: [{a: 1}]}. The ancestors of the inner object would be the array and then the outer object.

Originally posted by @NightProgramming in #23 (comment)

[RebeccaStevens]

@NightProgramming

I can always add more meta data so long as it is pretty universal.

Providing the parent objects of the values shouldn't be too hard to do with a custom metaDataUpdater. I'll look into whether this could be easily added to the default meta data.

[RebeccaStevens]

@NightProgramming

I just released 3.0.0-beta.4 which has this feature.
Note: There may be some breaking changes between that release and the previous (3.0.0-beta.3)