{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
  "elmType": "div",
  "txtContent": "@currentField",
  "style": {
    "text-decoration": "=if([$Complete],'line-through','inherit')"
  },
  "attributes": {
    "class": "ms-fontColor-neutralPrimary"
  }
}