Compare object of arrays by property include nulls and secondary property

sort.js

    function compareProperty(a, b) {
      return a || b ? (!a ? 1 : !b ? -1 : a.localeCompare(b)) : 0
    }

    function myComparer(a, b) {
      return compareProperty(a.jewelerName, b.jewelerName) || compareProperty(a.name, b.name)
    }

    // Flatten array
    const flattened = [].concat.apply([], tableAssignmentsLookup)
    const csvRows = flattened.sort(myComparer)