feat: add implicit merge for if block instead of merge

Closes #7

ts/server/src/utils/example1.fhir.spec.ts

@@ -0,0 +1,161 @@
+import { QuestionnaireResponse } from 'fhir/r4b';
+import { resolveTemplate } from './extract';
+import * as fhirpath_r4_model from 'fhirpath/fhir-context/r4';
+
+const qr: QuestionnaireResponse = {
+    resourceType: 'QuestionnaireResponse',
+    status: 'completed',
+    item: [
+        {
+            linkId: 'name',
+            item: [
+                {
+                    linkId: 'last-name',
+                    answer: [
+                        {
+                            valueString: 'Beda',
+                        },
+                    ],
+                },
+                {
+                    linkId: 'first-name',
+                    answer: [
+                        {
+                            valueString: 'Ilya',
+                        },
+                    ],
+                },
+                {
+                    linkId: 'middle-name',
+                    answer: [
+                        {
+                            valueString: 'Alekseevich',
+                        },
+                    ],
+                },
+            ],
+        },
+        {
+            linkId: 'birth-date',
+            answer: [
+                {
+                    valueDate: '2023-05-01',
+                },
+            ],
+        },
+        {
+            linkId: 'gender',
+            answer: [
+                {
+                    valueCoding: { code: 'male' },
+                },
+            ],
+        },
+        {
+            linkId: 'ssn',
+            answer: [
+                {
+                    valueString: '123',
+                },
+            ],
+        },
+        {
+            linkId: 'mobile',
+            answer: [
+                {
+                    valueString: '11231231231',
+                },
+            ],
+        },
+    ],
+};
+
+const template1 = {
+    resourceType: 'Patient',
+    name: [
+        {
+            family: "{{ QuestionnaireResponse.repeat(item).where(linkId='last-name').answer.value }}",
+            given: [
+                "{{ QuestionnaireResponse.repeat(item).where(linkId='first-name').answer.value }}",
+                "{{ QuestionnaireResponse.repeat(item).where(linkId='middle-name').answer.value }}",
+            ],
+        },
+    ],
+    birthDate: "{{ QuestionnaireResponse.item.where(linkId='birth-date').answer.value }}",
+    gender: "{{ QuestionnaireResponse.item.where(linkId='gender').answer.valueCoding.code }}",
+    telecom: [
+        {
+            system: 'phone',
+            value: "{{ QuestionnaireResponse.item.where(linkId='mobile').answer.value }}",
+        },
+    ],
+    identifier: [
+        {
+            system: 'http://hl7.org/fhir/sid/us-ssn',
+            value: "{{ QuestionnaireResponse.item.where(linkId='ssn').answer.value }}",
+        },
+    ],
+};
+
+
+const template2 = {
+    resourceType: 'Patient',
+    name: {
+        "{{ QuestionnaireResponse.item.where(linkId='name') }}": {
+            family: "{{ item.where(linkId='last-name').answer.valueString }}",
+            given: [
+                "{{ item.where(linkId='first-name').answer.valueString }}",
+                "{{ item.where(linkId='middle-name').answer.valueString }}",
+            ],
+        },
+    },
+    birthDate: "{{ QuestionnaireResponse.item.where(linkId='birth-date').answer.value }}",
+    gender: "{{ QuestionnaireResponse.item.where(linkId='gender').answer.valueCoding.code }}",
+    telecom: [
+        {
+            system: 'phone',
+            value: "{{ QuestionnaireResponse.item.where(linkId='mobile').answer.value }}",
+        },
+    ],
+    identifier: [
+        {
+            system: 'http://hl7.org/fhir/sid/us-ssn',
+            value: "{{ QuestionnaireResponse.item.where(linkId='ssn').answer.value }}",
+        },
+    ],
+};
+
+const result = {
+    birthDate: '2023-05-01',
+    gender: 'male',
+    identifier: [
+        {
+            system: 'http://hl7.org/fhir/sid/us-ssn',
+            value: '123',
+        },
+    ],
+    name: [
+        {
+            family: 'Beda',
+            given: ['Ilya', 'Alekseevich'],
+        },
+    ],
+    resourceType: 'Patient',
+    telecom: [
+        {
+            system: 'phone',
+            value: '11231231231',
+        },
+    ],
+};
+
+describe('Extraction', () => {
+    test('Simple transformation', () => {
+        expect(resolveTemplate(qr, template1, {}, fhirpath_r4_model)).toStrictEqual(result);
+    });
+
+    test('List transformation', () => {
+        expect(resolveTemplate(qr, template2, {}, fhirpath_r4_model)).toStrictEqual(result);
+    });
+});
+