#ctx.collectionField

The CollectionField instance associated with the current RunJS execution context, used to access field metadata, types, validation rules, and association information. It only exists when the field is bound to a collection definition; custom/virtual fields may be null.

#Use Cases

Note: ctx.collectionField is only available when the field is bound to a Collection definition; it is usually undefined in scenarios like JSBlock independent blocks or action events without field binding. It is recommended to check for null values before use.

#Type Definition

collectionField: CollectionField | null | undefined;

#Common Properties

#Common Methods

#Examples

#Branch rendering based on field type

if (!ctx.collectionField) return null;
const { interface: iface } = ctx.collectionField;
if (['m2o', 'o2m', 'm2m'].includes(iface)) {
  // Association field: display associated records
  const target = ctx.collectionField.targetCollection;
  // ...
} else if (iface === 'select' || iface === 'radioGroup') {
  const options = ctx.collectionField.enum || [];
  // ...
}

#Determine if it is an association field and access the target collection

if (ctx.collectionField?.isAssociationField()) {
  const targetCol = ctx.collectionField.targetCollection;
  const titleField = targetCol?.titleCollectionField?.name;
  // Process according to the target collection structure
}

#Get enumeration options

const options = ctx.collectionField?.enum ?? [];
const labels = options.map((o) => (typeof o === 'object' ? o.label : o));

#Conditional rendering based on read-only/view mode

const { Input } = ctx.libs.antd;
if (ctx.collectionField?.readonly) {
  ctx.render(<span>{ctx.getValue?.() ?? '-'}</span>);
} else {
  ctx.render(<Input onChange={(e) => ctx.setValue?.(e.target.value)} />);
}

#Get the title field of the target collection

// When displaying an association field, use targetCollectionTitleField to get the title field name
const titleField = ctx.collectionField?.targetCollectionTitleField;
const titleKey = titleField?.name ?? 'title';
const assocValue = ctx.getValue?.() ?? ctx.record?.[ctx.collectionField?.name];
const label = assocValue?.[titleKey];

#Relationship with ctx.collection

ctx.collection usually represents the collection bound to the current block; ctx.collectionField represents the definition of the current field in the collection. In scenarios like sub-tables or association fields, the two may differ.

#Notes

• In scenarios such as JSBlock or JSAction (without field binding), ctx.collectionField is usually undefined. It is recommended to use optional chaining before access.
• If a custom JS field is not bound to a collection field, ctx.collectionField may be null.
• targetCollection only exists for association type fields (e.g., m2o, o2m, m2m); enum only exists for fields with options like select or radioGroup.

#Related

• ctx.collection: Collection associated with the current context
• ctx.model: Model where the current execution context is located
• ctx.blockModel: Parent block carrying the current JS
• ctx.getValue(), ctx.setValue(): Read and write the current field value