From 8a864d0b4516cd0df0aea74710bba9104701b528 Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 11:20:54 +0000
Subject: [PATCH 01/13] change cck sample code

---
 test/cck/parameter-types/support.mjs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/cck/parameter-types/support.mjs b/test/cck/parameter-types/support.mjs
index faee4ae6..b1829145 100644
--- a/test/cck/parameter-types/support.mjs
+++ b/test/cck/parameter-types/support.mjs
@@ -14,7 +14,7 @@ class Flight {
 ParameterType({
   name: 'flight',
   regexp: /([A-Z]{3})-([A-Z]{3})/,
-  transformer(from, to) {
+  transformer(t, from, to) {
     return new Flight(from, to)
   },
 })

From 04c98a609ba6018260cd34de56c928f3522f93ff Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 13:47:53 +0000
Subject: [PATCH 02/13] redo parameter type interface

---
 src/index.ts           |  4 +++-
 src/types.ts           |  3 ++-
 src/wrapTransformer.ts | 12 ++++++++++++
 3 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 src/wrapTransformer.ts

diff --git a/src/index.ts b/src/index.ts
index e0476361..22e284a6 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,6 +3,7 @@ import { Promisable } from 'type-fest'
 import { makeSourceReference } from './makeSourceReference.js'
 import { coreBuilder, extraBuilder } from './runner/state.js'
 import { HookFunction, HookOptions, ParameterTypeOptions, StepFunction, World } from './types.js'
+import { wrapTransformer } from './wrapTransformer.js'
 
 export * from './types.js'
 export { DataTable } from '@cucumber/core'
@@ -37,7 +38,7 @@ export function WorldCreator(
  * @example ParameterType(\{
  *   name: 'flight',
  *   regexp: /([A-Z]\{3\})-([A-Z]\{3\})/,
- *   transformer(from, to) \{
+ *   transformer(t, from, to) \{
  *     return new Flight(from, to)
  *   \},
  * \})
@@ -45,6 +46,7 @@ export function WorldCreator(
 export function ParameterType(options: ParameterTypeOptions) {
   coreBuilder.parameterType({
     ...options,
+    transformer: wrapTransformer(options.transformer),
     sourceReference: makeSourceReference(),
   })
 }
diff --git a/src/types.ts b/src/types.ts
index 7e8ae9a8..69c2d9cc 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -103,11 +103,12 @@ export type ParameterTypeOptions = {
   /**
    * A function for transforming the matched values to another object before passing to
    * the step function
+   * @param context - context object for the current test
    * @param match - matched values from the regular expression
    * @remarks
    * If not provided, the raw matched value(s) will be passed to the step function.
    */
-  transformer?: (this: World, ...match: string[]) => unknown
+  transformer?: (this: World, context: TestCaseContext, ...match: string[]) => unknown
   /**
    * Whether this parameter type should be used when suggesting snippets for missing step
    * definitions
diff --git a/src/wrapTransformer.ts b/src/wrapTransformer.ts
new file mode 100644
index 00000000..2744fa9c
--- /dev/null
+++ b/src/wrapTransformer.ts
@@ -0,0 +1,12 @@
+import { NewParameterType } from '@cucumber/core/dist/types.js'
+
+import { ParameterTypeOptions, TestCaseContext } from './types.js'
+
+export function wrapTransformer(transformer: ParameterTypeOptions['transformer']): NewParameterType['transformer'] {
+  if (transformer) {
+    return function(this: TestCaseContext, ...match: string[]) {
+      return transformer.apply(this.world, [this, ...match])
+    }
+  }
+  return undefined
+}
\ No newline at end of file

From fa5c5cfa3a18137c12839c596a4e600a094590ae Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 13:54:14 +0000
Subject: [PATCH 03/13] implement with new core changes

---
 src/runner/ExecutableTestStep.ts | 12 +++++++++---
 src/wrapTransformer.ts           |  8 +++++---
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/runner/ExecutableTestStep.ts b/src/runner/ExecutableTestStep.ts
index c7a69a35..9f840507 100644
--- a/src/runner/ExecutableTestStep.ts
+++ b/src/runner/ExecutableTestStep.ts
@@ -1,7 +1,7 @@
 import { TestContext } from 'node:test'
 import { styleText } from 'node:util'
 
-import { AssembledTestStep } from '@cucumber/core'
+import { AssembledTestStep, DataTable } from '@cucumber/core'
 import { TestStepResult } from '@cucumber/messages'
 
 import { makeTimestamp } from '../makeTimestamp.js'
@@ -39,9 +39,15 @@ export class ExecutableTestStep {
   async execute(nodeTestContext: TestContext) {
     let success = false
     try {
-      const { fn, args } = this.assembledStep.prepare(this.parent.world)
+      const { fn, args, dataTable, docString } = this.assembledStep.prepare()
       const context = this.makeContext(nodeTestContext)
-      const returned = await fn(context, ...args)
+      const fnArgs: Array<unknown> = [context, ...args.map((arg) => arg.getValue(context))]
+      if (dataTable) {
+        fnArgs.push(DataTable.from(dataTable))
+      } else if (docString) {
+        fnArgs.push(docString.content)
+      }
+      const returned = await fn.apply(context.world, fnArgs)
       if (returned === 'skipped') {
         context.skip()
       } else if (returned === 'pending') {
diff --git a/src/wrapTransformer.ts b/src/wrapTransformer.ts
index 2744fa9c..4f4806cc 100644
--- a/src/wrapTransformer.ts
+++ b/src/wrapTransformer.ts
@@ -2,11 +2,13 @@ import { NewParameterType } from '@cucumber/core/dist/types.js'
 
 import { ParameterTypeOptions, TestCaseContext } from './types.js'
 
-export function wrapTransformer(transformer: ParameterTypeOptions['transformer']): NewParameterType['transformer'] {
+export function wrapTransformer(
+  transformer: ParameterTypeOptions['transformer']
+): NewParameterType['transformer'] {
   if (transformer) {
-    return function(this: TestCaseContext, ...match: string[]) {
+    return function (this: TestCaseContext, ...match: string[]) {
       return transformer.apply(this.world, [this, ...match])
     }
   }
   return undefined
-}
\ No newline at end of file
+}

From 7bd97c3cb2077dd9c297d2d74bf01d7fac0ba227 Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 18:09:15 +0000
Subject: [PATCH 04/13] bump core library

---
 package-lock.json | 8 ++++----
 package.json      | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index f2d98e72..216778eb 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -12,7 +12,7 @@
         "@babel/generator": "^7.28.5",
         "@babel/types": "^7.28.5",
         "@cucumber/ci-environment": "12.0.0",
-        "@cucumber/core": "0.7.0",
+        "@cucumber/core": "0.8.0",
         "@cucumber/cucumber-expressions": "18.0.1",
         "@cucumber/gherkin": "37.0.0",
         "@cucumber/html-formatter": "22.1.0",
@@ -139,9 +139,9 @@
       "license": "MIT"
     },
     "node_modules/@cucumber/core": {
-      "version": "0.7.0",
-      "resolved": "https://registry.npmjs.org/@cucumber/core/-/core-0.7.0.tgz",
-      "integrity": "sha512-dEjZuQj6LmXkOvn7fphxf+t9nUpNT+KNLsmXnmmC4L/emonniNhb59FpuYEwNOhUZhJn7Irha2t4WSKATKGDyw==",
+      "version": "0.8.0",
+      "resolved": "https://registry.npmjs.org/@cucumber/core/-/core-0.8.0.tgz",
+      "integrity": "sha512-BY/GE96ZijyVlz47Xt8vE3XRSrYSUewLjJlQVVsX3SiPRfsWaO8lTl6PyaH2Pid+l0GeVVNII+ynXHD7l5npJA==",
       "license": "MIT",
       "peerDependencies": {
         "@cucumber/cucumber-expressions": "*",
diff --git a/package.json b/package.json
index ec236f47..32e9b92d 100644
--- a/package.json
+++ b/package.json
@@ -32,7 +32,7 @@
     "@babel/generator": "^7.28.5",
     "@babel/types": "^7.28.5",
     "@cucumber/ci-environment": "12.0.0",
-    "@cucumber/core": "0.7.0",
+    "@cucumber/core": "0.8.0",
     "@cucumber/cucumber-expressions": "18.0.1",
     "@cucumber/gherkin": "37.0.0",
     "@cucumber/html-formatter": "22.1.0",

From 4d3017aefc9eccfb5feb75dd5fd27d8135ea0237 Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 18:10:18 +0000
Subject: [PATCH 05/13] regenerate api spec

---
 cucumber-node.api.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cucumber-node.api.md b/cucumber-node.api.md
index 18c1eb98..bd542729 100644
--- a/cucumber-node.api.md
+++ b/cucumber-node.api.md
@@ -48,7 +48,7 @@ export function ParameterType(options: ParameterTypeOptions): void;
 export type ParameterTypeOptions = {
     name: string;
     regexp: RegExp | string | readonly RegExp[] | readonly string[];
-    transformer?: (this: World, ...match: string[]) => unknown;
+    transformer?: (this: World, context: TestCaseContext, ...match: string[]) => unknown;
     useForSnippets?: boolean;
     preferForRegexpMatch?: boolean;
 };

From 548bb24b3b380f82469ba53edae63b846ebc609a Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:03:51 +0000
Subject: [PATCH 06/13] improve typing and testing

---
 src/types.ts                |  8 +++++++-
 src/wrapTransformer.spec.ts | 40 +++++++++++++++++++++++++++++++++++++
 src/wrapTransformer.ts      |  6 +++---
 3 files changed, 50 insertions(+), 4 deletions(-)
 create mode 100644 src/wrapTransformer.spec.ts

diff --git a/src/types.ts b/src/types.ts
index 69c2d9cc..8165f879 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -108,7 +108,7 @@ export type ParameterTypeOptions = {
    * @remarks
    * If not provided, the raw matched value(s) will be passed to the step function.
    */
-  transformer?: (this: World, context: TestCaseContext, ...match: string[]) => unknown
+  transformer?: TransformerFunction
   /**
    * Whether this parameter type should be used when suggesting snippets for missing step
    * definitions
@@ -139,6 +139,12 @@ export type HookOptions = {
   tags?: string
 }
 
+export type TransformerFunction = (
+  this: World,
+  context: TestCaseContext,
+  ...match: string[]
+) => unknown
+
 /**
  * A function to be executed as a hook
  * @public
diff --git a/src/wrapTransformer.spec.ts b/src/wrapTransformer.spec.ts
new file mode 100644
index 00000000..b4bcae4f
--- /dev/null
+++ b/src/wrapTransformer.spec.ts
@@ -0,0 +1,40 @@
+import { expect } from 'chai'
+
+import { TestCaseContext } from './types.js'
+import { wrapTransformer } from './wrapTransformer.js'
+
+describe('wrapTransformer', () => {
+  it('returns undefined when transformer is undefined', () => {
+    const result = wrapTransformer(undefined)
+
+    expect(result).to.eq(undefined)
+  })
+
+  it('wrapped transformer handles multiple match arguments', () => {
+    const transformer = function (
+      this: any, // eslint-disable-line @typescript-eslint/no-explicit-any
+      context: TestCaseContext,
+      match1: string,
+      match2: string
+    ) {
+      return {
+        fromThis: this.foo,
+        fromContext: context.world.foo,
+        match1,
+        match2,
+      }
+    }
+
+    const wrapped = wrapTransformer(transformer)!
+    const testContext = { world: { foo: 'bar' } } as TestCaseContext
+
+    const result = wrapped.call(testContext, 'a', 'b')
+
+    expect(result).to.deep.eq({
+      fromThis: 'bar',
+      fromContext: 'bar',
+      match1: 'a',
+      match2: 'b',
+    })
+  })
+})
diff --git a/src/wrapTransformer.ts b/src/wrapTransformer.ts
index 4f4806cc..2105f376 100644
--- a/src/wrapTransformer.ts
+++ b/src/wrapTransformer.ts
@@ -1,9 +1,9 @@
-import { NewParameterType } from '@cucumber/core/dist/types.js'
+import { NewParameterType } from '@cucumber/core'
 
-import { ParameterTypeOptions, TestCaseContext } from './types.js'
+import { TestCaseContext, TransformerFunction } from './types.js'
 
 export function wrapTransformer(
-  transformer: ParameterTypeOptions['transformer']
+  transformer?: TransformerFunction
 ): NewParameterType['transformer'] {
   if (transformer) {
     return function (this: TestCaseContext, ...match: string[]) {

From ce7032df64431fa25f91a360c7c0ada9fcd936f7 Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:05:47 +0000
Subject: [PATCH 07/13] update api again

---
 cucumber-node.api.md | 5 ++++-
 src/types.ts         | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/cucumber-node.api.md b/cucumber-node.api.md
index bd542729..e87d927f 100644
--- a/cucumber-node.api.md
+++ b/cucumber-node.api.md
@@ -48,7 +48,7 @@ export function ParameterType(options: ParameterTypeOptions): void;
 export type ParameterTypeOptions = {
     name: string;
     regexp: RegExp | string | readonly RegExp[] | readonly string[];
-    transformer?: (this: World, context: TestCaseContext, ...match: string[]) => unknown;
+    transformer?: TransformerFunction;
     useForSnippets?: boolean;
     preferForRegexpMatch?: boolean;
 };
@@ -71,6 +71,9 @@ export type TestCaseContext = {
 // @public
 export function Then(pattern: string | RegExp, fn: StepFunction): void;
 
+// @public
+export type TransformerFunction = (this: World, context: TestCaseContext, ...match: string[]) => unknown;
+
 // @public
 export function When(pattern: string | RegExp, fn: StepFunction): void;
 
diff --git a/src/types.ts b/src/types.ts
index 8165f879..69652a9b 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -139,6 +139,10 @@ export type HookOptions = {
   tags?: string
 }
 
+/**
+ * A function to transform a raw parameter value into a user-defined type
+ * @public
+ */
 export type TransformerFunction = (
   this: World,
   context: TestCaseContext,

From bdee9d9bb1bdbe9dbefc11377c8a39c8117fa3ae Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:18:58 +0000
Subject: [PATCH 08/13] commentary

---
 src/wrapTransformer.ts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/wrapTransformer.ts b/src/wrapTransformer.ts
index 2105f376..3310fb6c 100644
--- a/src/wrapTransformer.ts
+++ b/src/wrapTransformer.ts
@@ -2,6 +2,13 @@ import { NewParameterType } from '@cucumber/core'
 
 import { TestCaseContext, TransformerFunction } from './types.js'
 
+/*
+ * Turn the user-supplied transformer function into one we can provide to
+ * the ParameterTypeRegistry - which only supports a custom `this` for
+ * modifying behaviour - while maintaining our signature of prepending
+ * the context as the first arg, and setting the world as `this` for
+ * continuity when coming from cucumber-js
+ */
 export function wrapTransformer(
   transformer?: TransformerFunction
 ): NewParameterType['transformer'] {

From b5428ea5f9f9933108a0f46a136e625ef65d5e1d Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:20:43 +0000
Subject: [PATCH 09/13] update CHANGELOG.md

---
 CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 64dc287a..604fe37f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Provide source maps for pickles ([#149](https://github.com/cucumber/cucumber-node/pull/149))
 - Support returning "skipped" or "pending" from user code ([#155](https://github.com/cucumber/cucumber-node/pull/155))
 
+### Changed
+- BREAKING CHANGE: Prepend context to parameter transformers ([#160](https://github.com/cucumber/cucumber-node/pull/160))
+
 ## [0.5.0] - 2025-11-17
 ### Added
 - Support Node.js 24 ([#67](https://github.com/cucumber/cucumber-node/pull/67))

From a66760291b16624f44a5f674fe48427987487fa4 Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:38:13 +0000
Subject: [PATCH 10/13] make cck sample nicer

---
 test/cck/parameter-types/support.mjs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/test/cck/parameter-types/support.mjs b/test/cck/parameter-types/support.mjs
index b1829145..67559731 100644
--- a/test/cck/parameter-types/support.mjs
+++ b/test/cck/parameter-types/support.mjs
@@ -14,9 +14,7 @@ class Flight {
 ParameterType({
   name: 'flight',
   regexp: /([A-Z]{3})-([A-Z]{3})/,
-  transformer(t, from, to) {
-    return new Flight(from, to)
-  },
+  transformer: (t, from, to) => new Flight(from, to),
 })
 
 Given('{flight} has been delayed', (t, flight) => {

From 968659e83f0fd3d01413acfe3ebd92f9b6c8f6cc Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:40:56 +0000
Subject: [PATCH 11/13] make doc example nicer too

---
 src/index.ts | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 22e284a6..dc4d00e6 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -38,9 +38,7 @@ export function WorldCreator(
  * @example ParameterType(\{
  *   name: 'flight',
  *   regexp: /([A-Z]\{3\})-([A-Z]\{3\})/,
- *   transformer(t, from, to) \{
- *     return new Flight(from, to)
- *   \},
+ *   transformer: (t, from, to) => new Flight(from, to)
  * \})
  */
 export function ParameterType(options: ParameterTypeOptions) {

From 393545a11bfe32aecdf6c830250df2f41675eb74 Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:47:09 +0000
Subject: [PATCH 12/13] trim doc comment

---
 src/types.ts | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/types.ts b/src/types.ts
index 69652a9b..d9bdb661 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -103,8 +103,6 @@ export type ParameterTypeOptions = {
   /**
    * A function for transforming the matched values to another object before passing to
    * the step function
-   * @param context - context object for the current test
-   * @param match - matched values from the regular expression
    * @remarks
    * If not provided, the raw matched value(s) will be passed to the step function.
    */

From 016ede6c0a98a6341dc5ed7ef8f96a5aabad3ec8 Mon Sep 17 00:00:00 2001
From: David Goss <david@davidgoss.co>
Date: Tue, 25 Nov 2025 19:48:48 +0000
Subject: [PATCH 13/13] clean up test

---
 src/wrapTransformer.spec.ts | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/wrapTransformer.spec.ts b/src/wrapTransformer.spec.ts
index b4bcae4f..d3e90604 100644
--- a/src/wrapTransformer.spec.ts
+++ b/src/wrapTransformer.spec.ts
@@ -10,7 +10,7 @@ describe('wrapTransformer', () => {
     expect(result).to.eq(undefined)
   })
 
-  it('wrapped transformer handles multiple match arguments', () => {
+  it('prepends context to args and uses world as this', () => {
     const transformer = function (
       this: any, // eslint-disable-line @typescript-eslint/no-explicit-any
       context: TestCaseContext,
@@ -27,7 +27,6 @@ describe('wrapTransformer', () => {
 
     const wrapped = wrapTransformer(transformer)!
     const testContext = { world: { foo: 'bar' } } as TestCaseContext
-
     const result = wrapped.call(testContext, 'a', 'b')
 
     expect(result).to.deep.eq({