FHIR Extensions

eSheet defines two custom FHIR extensions to preserve its layout model when exporting to FHIR Questionnaire resources. Both extensions use valueCode and round-trip cleanly through import/export.

Extension URL constants are exported from @esheet/adapters as FHIR_EXT.FIELD_WIDTH and FHIR_EXT.OPTION_LAYOUT.

---

field-width

URL: https://esheet.os.mieweb.org/docs/adapters/fhir/extensions#field-width

Controls the column width a questionnaire item occupies in a row-based layout grid. Corresponds to the width property on FieldWidth in the eSheet schema.

Value set

valueCode	Description
full	Spans the full row width (default)
half	Takes up half the row (2 per row)
third	Takes up a third of the row (3 per row)

When absent the field renders at full width.

Example

{
  "linkId": "first-name",
  "text": "First Name",
  "type": "string",
  "extension": [
    {
      "url": "https://esheet.os.mieweb.org/docs/adapters/fhir/extensions#field-width",
      "valueCode": "half"
    }
  ]
}

Applies to

All answer-bearing item types (string, text, boolean, decimal, integer, date, dateTime, time, url, choice, open-choice, attachment).

---

option-layout

URL: https://esheet.os.mieweb.org/docs/adapters/fhir/extensions#option-layout

Controls how the answer options of a choice item are rendered. Corresponds to the optionLayout property on OptionLayout in the eSheet schema.

Value set

valueCode	Description
stack	One option per line, stacked vertically (default)
wrap	Options flow horizontally and wrap to the next line

When absent the options render in stack layout.

Example

{
  "linkId": "preferred-contact",
  "text": "Preferred contact method",
  "type": "choice",
  "extension": [
    {
      "url": "https://esheet.os.mieweb.org/docs/adapters/fhir/extensions#option-layout",
      "valueCode": "wrap"
    }
  ],
  "answerOption": [
    { "valueCoding": { "code": "phone", "display": "Phone" } },
    { "valueCoding": { "code": "email", "display": "Email" } },
    { "valueCoding": { "code": "sms", "display": "SMS" } }
  ]
}

Applies to

choice and open-choice items that map to radio, check, or multitext field types.

---

Using with the adapter

Both extensions are written automatically by exportToFhir when the field definition includes width or optionLayout, and are read back by importFromFhir to restore those properties.

import { exportToFhir, FHIR_EXT } from '@esheet/adapters';

const form = {
  id: 'contact-form',
  fields: [
    {
      id: 'first-name',
      fieldType: 'text',
      question: 'First Name',
      width: 'half',
    },
    {
      id: 'preferred-contact',
      fieldType: 'radio',
      question: 'Preferred contact method',
      optionLayout: 'wrap',
      options: [
        { id: 'phone', value: 'Phone' },
        { id: 'email', value: 'Email' },
        { id: 'sms', value: 'SMS' },
      ],
    },
  ],
};

const questionnaire = exportToFhir(form);
// Each item's extension array will include FHIR_EXT.FIELD_WIDTH / FHIR_EXT.OPTION_LAYOUT

You can reference the extension URL constants directly:

console.log(FHIR_EXT.FIELD_WIDTH);
// 'https://esheet.os.mieweb.org/docs/adapters/fhir/extensions#field-width'

console.log(FHIR_EXT.OPTION_LAYOUT);
// 'https://esheet.os.mieweb.org/docs/adapters/fhir/extensions#option-layout'