Allow ExpressionsGroup.children to be optional

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- Allow ExpressionsGroup.children to be optional ([#43](https://github.com/cucumber/javascript-core/pull/43))
 
 ## [0.8.2] - 2026-01-12
 ### Changed

package.json

@@ -37,7 +37,7 @@
     "@cucumber/tag-expressions": "*"
   },
   "devDependencies": {
-    "@cucumber/cucumber-expressions": "^18.0.1",
+    "@cucumber/cucumber-expressions": "^19.0.0",
     "@cucumber/gherkin": "^38.0.0",
     "@cucumber/messages": "^32.0.0",
     "@cucumber/query": "^15.0.0",

src/makeTestPlan.spec.ts

@@ -555,10 +555,21 @@ describe('makeTestPlan', () => {
           fn: sinon.stub(),
           sourceReference: { uri: 'hooks.js', location: { line: 2, column: 1 } },
         })
+        .parameterType({
+          name: 'flight',
+          regexp: /([A-Z]{3})-([A-Z]{3})/,
+          transformer: sinon.stub(),
+          sourceReference: { uri: 'hooks.js', location: { line: 1, column: 1 } },
+        })
         .step({
           pattern: 'we scored {int} out of {int}',
           fn: sinon.stub(),
-          sourceReference: { uri: 'steps.js', location: { line: 1, column: 1 } },
+          sourceReference: { uri: 'steps.js', location: { line: 2, column: 1 } },
+        })
+        .step({
+          pattern: '{flight} has been delayed',
+          fn: sinon.stub(),
+          sourceReference: { uri: 'steps.js', location: { line: 3, column: 1 } },
         })
         .build()
 
@@ -572,31 +583,29 @@ describe('makeTestPlan', () => {
       expect(result.toEnvelopes()).to.deep.eq([
         {
           testCase: {
-            id: '7',
-            pickleId: '3',
+            id: '11',
+            pickleId: '5',
             testSteps: [
               {
-                hookId: '4',
-                id: '8',
+                hookId: '6',
+                id: '12',
               },
               {
-                id: '9',
-                pickleStepId: '2',
-                stepDefinitionIds: ['6'],
+                id: '13',
+                pickleStepId: '3',
+                stepDefinitionIds: ['9'],
                 stepMatchArgumentsLists: [
                   {
                     stepMatchArguments: [
                       {
                         group: {
-                          children: [],
                           start: 10,
                           value: '4',
                         },
                         parameterTypeName: 'int',
                       },
                       {
                         group: {
-                          children: [],
                           start: 19,
                           value: '5',
                         },
@@ -607,8 +616,36 @@ describe('makeTestPlan', () => {
                 ],
               },
               {
-                hookId: '5',
-                id: '10',
+                id: '14',
+                pickleStepId: '4',
+                stepDefinitionIds: ['10'],
+                stepMatchArgumentsLists: [
+                  {
+                    stepMatchArguments: [
+                      {
+                        group: {
+                          children: [
+                            {
+                              start: 0,
+                              value: 'LHR',
+                            },
+                            {
+                              start: 4,
+                              value: 'CDG',
+                            },
+                          ],
+                          start: 0,
+                          value: 'LHR-CDG',
+                        },
+                        parameterTypeName: 'flight',
+                      },
+                    ],
+                  },
+                ],
+              },
+              {
+                hookId: '7',
+                id: '15',
               },
             ],
             testRunStartedId,

src/makeTestPlan.ts

@@ -221,6 +221,12 @@ function fromPickleSteps(
 }
 
 function mapArgumentGroup(group: ExpressionsGroup): MessagesGroup {
+  if (!group.children) {
+    return {
+      start: group.start,
+      value: group.value,
+    }
+  }
   return {
     start: group.start,
     value: group.value,

testdata/parameters.feature

@@ -1,3 +1,4 @@
 Feature: a feature
   Scenario: a scenario
-    Given we scored 4 out of 5
+    Given we scored 4 out of 5
+    And LHR-CDG has been delayed