refactor(hermes): one width-suffix fold and one function-header test

The pretty (hermes-base) and raw (hermes-raw) dump readers each had their
own operand-width suffix fold and function-header regex; hermes-raw now
exports both. The two line splitters stay separate: only the raw one strips
CR, and unifying them would change the pretty pass on CRLF output, which no
test or CI job exercises.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: sunnylqm

src/utils/hermes-base.ts

@@ -37,7 +37,12 @@ import {
   LiteralResolver,
   literalBuffersFromBytes,
 } from './hermes-literals';
-import { auditRawHermesBytecode, hermesSemanticData } from './hermes-raw';
+import {
+  auditRawHermesBytecode,
+  foldWidthSuffix,
+  hermesSemanticData,
+  isFunctionHeader,
+} from './hermes-raw';
 import { hermesTimeout } from './hermes-timeout';
 import { t } from './i18n';
 import { webFetch } from './runtime';
@@ -1252,15 +1257,6 @@ function isLetter(code: number): boolean {
 }
 
 /** strip one operand-width suffix (LongIndex, Long, Short) off an opcode */
-function foldWidthSuffix(opcode: string): string {
-  for (const suffix of ['LongIndex', 'Long', 'Short']) {
-    if (opcode.length > suffix.length && opcode.endsWith(suffix)) {
-      return opcode.slice(0, -suffix.length);
-    }
-  }
-  return opcode;
-}
-
 /** Split a readable stream into lines without readline (Bun's readline async iterator misbehaves when pulled manually). */
 async function* streamLines(
   stream: NodeJS.ReadableStream,
@@ -1334,10 +1330,6 @@ const DUMP_STDERR_KEEP = 4 * 1024;
 /** a diagnostic line is cut to this many characters */
 const DETAIL_LINE_MAX = 120;
 
-function isFunctionHeader(line: string): boolean {
-  return /^(?:Function|NCFunction|Constructor)</.test(line);
-}
-
 /**
  * Structured reader over one `hermesc -dump-bytecode -pretty-disassemble`
  * stream. Everything before the functions is either the string table (kept

src/utils/hermes-raw.ts

@@ -275,8 +275,19 @@ interface RawInstruction {
 }
 
 /** Remove encoding-width suffixes; operand values remain part of the audit. */
-function foldWidth(opcode: string): string {
-  return opcode.replace(/(?:LongIndex|Long|Short)$/, '');
+/** The opcode without its operand-width suffix (`GetByIdLong` → `GetById`). */
+export function foldWidthSuffix(opcode: string): string {
+  for (const suffix of ['LongIndex', 'Long', 'Short']) {
+    if (opcode.length > suffix.length && opcode.endsWith(suffix)) {
+      return opcode.slice(0, -suffix.length);
+    }
+  }
+  return opcode;
+}
+
+/** The first line of a function in either dump. */
+export function isFunctionHeader(line: string): boolean {
+  return /^(?:Function|NCFunction|Constructor)</.test(line);
 }
 
 /**
@@ -382,7 +393,7 @@ export function normalizeRawHermesFunction(
   const literal = new LiteralResolver(buffers, data.strings);
   const output = [fn.metadata];
   for (const inst of instructions) {
-    const op = foldWidth(inst.opcode);
+    const op = foldWidthSuffix(inst.opcode);
     const values = inst.operands.map((o) => o.value);
     const refs = STRING_OPERANDS[op] ?? [];
     const operands: unknown[] = inst.operands.map((operand, i) => {
@@ -568,7 +579,7 @@ export async function auditRawHermesBytecode(
     const normalize = (body: string[]) =>
       normalizeRawHermesFunction(body, data[side], index++, buffers[side]);
     for await (const line of linesOf(children[side].stdout!)) {
-      if (/^(?:Function|NCFunction|Constructor)</.test(line)) {
+      if (isFunctionHeader(line)) {
         if (lines) yield normalize(lines);
         lines = [];
       } else if (