OpenSpecimen allows the initialization of field values using other field values (core or custom fields).

For example:

The visit date can be set to default as the registration date.
Specimen collection date => Registration date/Visit date
Created on => Registration date
Accession date (custom field) => Registration date/Visit date

Example 1: By using "defaultValue": "field:visit.visitDate", the collection date is set to show visit date as the default value.

{
  "name": "specimen.collectionEvent.time",
  "caption": "Collection Time",
  "type": "datetime",
  "defaultValue": "field:visit.visitDate", //visit date value will be displayed as default
  "optional": true,
  "showIf": {
    "op": "AND",
    "rules": [
      {
        "field": "specimen.lineage",
        "op": "==",
        "value": "'New'"
      }
    ]
  }
}

Example 2: By using "defaultValue" : "field: specimen.parent.extensionDetail.attrsMap.ST2" code in "derivedSpecimens" section, the custom field value from parent specimen will be defaulted to its derived specimens.

Note:

To make this code work, you need to create parent specimens first.
Once you create the parent specimen, you can add derivatives/aliquots.

{
   "name" : "specimen.extensionDetail.attrsMap.ST2",
   "baseField" : "specimen.extensionDetail.attrsMap.ST2",
   "caption" : "Cell Line ID",
   "defaultValue" : "field: specimen.parent.extensionDetail.attrsMap.ST2",
   "width" : "80px",
   "optional" : false
},

Example 3: By using "defaultValue" : "field: specimen.parent.initialQty" code in "derivedSpecimens" section, the initial quantity value from the parent specimen will be defaulted to its derived specimens.

Note:

To make this code work, you need to create parent specimens first.
Once you create the parent specimen, you can add derivatives/aliquots.

{
        "name" : "specimen.initialQty",
        "caption" : "Quantity",
        "type" : "specimen-quantity",
        "defaultValue" : "field: specimen.parent.initialQty",
        "optional" : true
      },