S31 stock-lines

{
  "mark": "line",
  "x": [
    {
      "kind": "dimension",
      "ref": {
        "dimension": "Date"
      },
      "role": "continuous"
    }
  ],
  "y": [
    {
      "kind": "metric",
      "metric": "stock_units"
    }
  ],
  "color": {
    "kind": "dimension",
    "ref": {
      "dimension": "product"
    }
  }
}

{
  "steps": [
    {
      "kind": "select",
      "metric": "stock_units",
      "transform": null,
      "within": [],
      "along": null,
      "alias": null
    }
  ],
  "by": [
    {
      "ref": {
        "dimension": "Date",
        "transforms": []
      },
      "alias": null
    },
    {
      "ref": {
        "dimension": "product",
        "transforms": []
      },
      "alias": null
    }
  ],
  "slice": [],
  "order_by": [
    {
      "ref": "Date",
      "direction": "asc"
    },
    {
      "ref": "product",
      "direction": "asc"
    }
  ],
  "limit": null
}