example of munging JSON using jq and still getting valid JSON

jq.sh

#!/bin/bash

cat item.json | jq 'map( {
  amount: .amount,
  yieldFactor: .yieldFactor,
  servingSize: .servingSize | { gramsEntered: .gramsEntered },
  measures: .measures | map( {
    amount: .amount,
    gramsPerUnit: .gramsPerUnit
  }),
  foodComponents: .foodComponents
})'