> Replacing commas with whitespace sounds to me like replacing a very minor irritant with a constant full-body rash

Both vivid and accurate.

In order to combat trailing commas I normally place the comma on the following line, e.g.

    { "time": "3 minutes past four"
    , "age": 229
    , "sex": "monoecious species"
    , "appearance": "Tree-like.  It's a tree."
    }

    uint8_t *data    // Yada
          , *buffer  // Ya
          ;

    var javascript
      , variable = 6
      , declarations = [ "This is taking too long", "Yep" ]
      , mix = [ "Flour", "Sugar", "Water" ]
      , types = { 'old'     : (d) => { return d < new Date }
                , 'new'     : (d) => { return d > new Date }
                , 'borrowed': (o) => { return false }
                , 'blue'    : (c) => { return true }
                }
      , regularly = new Date().toISOString()
      ;
    

With such a format there is only ever a problem deleting the first line, which I find is much much harder to do without also noticing what you've done to the larger statement.