score:0

Accepted answer
var query = array
    // filter out array items that are not objects
    .oftype<jobject>()
    // select the jproperty with the specified key
    .select(o => o.property(key))
    // filter for null (property was not found)
    .where(p => p != null)
    // and select a new jobject with just this property
    .select(p => new jobject(p));

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