Support stringifyStep internally

Note: Chrome doesn't support this yet (see https://crbug.com/1351649)

Author: nickserv

src/LineWriterImpl.ts

@@ -1,5 +1,6 @@
 import {
   stringify,
+  stringifyStep,
   type LineWriter,
   type NavigateStep,
   type Selector,
@@ -43,7 +44,7 @@ export class Extension implements StringifyExtension {
     out.appendLine("})")
   }
 
-  async stringifyStep(out: LineWriter, step: Step, flow: UserFlow) {
+  async stringifyStep(out: LineWriter, step: Step, flow?: UserFlow) {
     switch (step.type) {
       case "change":
         out.appendLine(
@@ -82,7 +83,10 @@ export class Extension implements StringifyExtension {
         )
         break
       case "navigate":
-        if (step === flow.steps.find((step) => step.type === "navigate")) {
+        if (
+          !flow ||
+          step === flow.steps.find((step) => step.type === "navigate")
+        ) {
           for (const { url, title } of step.assertedEvents ?? []) {
             if (url) {
               out.appendLine(`expect(location.href).toBe("${url}")`)
@@ -130,6 +134,10 @@ if (process.env.NODE_ENV !== "test") {
     stringify(recording: UserFlow) {
       return stringify(recording, { extension: new Extension() })
     }
+
+    stringifyStep(step: Step) {
+      return stringifyStep(step, { extension: new Extension() })
+    }
   }
 
   chrome.devtools.recorder.registerRecorderExtensionPlugin(

src/index.ts

@@ -2,13 +2,13 @@ import { readFile } from "fs/promises"
 import { join } from "path"
 import {
   stringify,
+  stringifyStep,
   type Selector,
   type Step,
   type UserFlow,
 } from "@puppeteer/replay"
 import { Extension } from "."
 import flow from "./fixtures/Example.json"
-import { LineWriterImpl } from "./LineWriterImpl"
 
 const extension = new Extension()
 const selectors: Selector[] = [["aria/Test"], ["#test"]]
@@ -108,9 +108,7 @@ describe("Extension", () => {
         "await waitFor(() => Promise.resolve())",
       ],
     ])("%p", async (step, expected) => {
-      const writer = new LineWriterImpl("  ")
-      await extension.stringifyStep(writer, step, { title: "", steps: [step] })
-      expect(writer.toString()).toBe(expected)
+      expect(await stringifyStep(step, { extension })).toBe(`${expected}\n`)
     })
   })
 })