I wish to include a conditional statement within a data_generator element, but it fails to work for me. what is wrong?

[ruteclrp]

I am making up this card which shall select the right attribute content for the data generator to return the data for the graph

type: custom:apexcharts-card
experimental:
color_threshold: true
graph_span: 1d
hours_12: false
yaxis:

• min: 0
  header:
  title: Energy price tomorrow (dkk/kWh)
  show: true
  span:
  start: day
  offset: +1d
  series:
• entity: sensor.energi_data_service
  color_threshold:
  • value: 0.5
    color: blue
  • value: 1.5
    color: cyan
  • value: 2.5
    color: orange
  • value: 3.5
    color: red
    type: column
    float_precision: 2
    data_generator: |
    if (entity.attributes.raw_tomorrow === "-") {
    return entity.attributes.forecast.map((hour, index) => {
    return [new Date(hour["hour"]).getTime(),
    entity.attributes.forecast[index]["price"]];
    }else {
    return entity.attributes.raw_tomorrow.map((hour, index) => {
    return [new Date(hour["hour"]).getTime(),
    entity.attributes.raw_tomorrow[index]["price"]];
    }
    });

each data generator element works in isolation, but wrapped within a conditional statement makes it fail.
I am at odds as to what goes wrong here?