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function merge(l1, l2) {
	const se = new Set(l1);
	l2.forEach(e => se.add(e))
	return [...se]
}

const x = Object.keys(old).reduce((acc, cur) => {
	acc[cur] = merge(old[cur], neww[cur]);
	return acc
}, {})

let y = null;
y = merge(old.DF5, old.DF16)
y = merge(y, old.DF19)
y = merge(y, old.DF20)
y = merge(y, old.DF21)