将MongoDB聚合中的匹配和查找与布尔值或

我想在MongoDB中完成以下类似SQL的操作

SELECT contentItem._id, contentitem.text
FROM contentItems
WHERE contentItem.metadata.color = 'yellow'
UNION
SELECT contentItem._id, contentitem.text
FROM contentItems
WHERE contentItems.contentSets IN (
    SELECT contentSet._id FROM contentSets WHERE contentSet.metadata.color= 'yellow'
)

也可以这样做

SELECT contentItem._id, contentitem.text
FROM contentItems
WHERE (
    contentItem.metadata.color = 'yellow'
) OR contentItems.contentSets IN (
    SELECT contentSet._id FROM contentSets WHERE contentSet.metadata.color = 'yellow'
)

这两半我都能做

db.getCollection('contentItems').aggregate([
    {
        '$match': {
            'metadata.color': { '$eq': 'yellow' }
        }
    }
])

和

db.getCollection('contentItems').aggregate([
    {'$unwind': '$contentSets'},
    {
        '$lookup': {
            'from': 'contentSets',
            'localField': 'contentSets',
            'foreignField': '_id',
            'as': 'matchedContentSets'
        }
    },
    {
        '$match': {
            'matchedContentSets.metadata.color': { '$eq': 'yellow' }
        }
    }
])

但我不知道如何把这些数据结合起来。