From bdbe11d16abe1250e8b8a422fd48b60e10866611 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9CSebastian?=
 <64795732+slegarraga@users.noreply.github.com>
Date: Thu, 6 Aug 2026 05:14:24 -0400
Subject: [PATCH] fix: make exact-match whitespace collapsing opt-out

---
 README.md                  |  2 +-
 src/scorers/exact-match.ts |  6 ++++--
 src/scorers/util.ts        |  7 +++++--
 tests/scorers.test.ts      | 22 ++++++++++++++++++++++
 4 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index b66ca8d..01406f3 100644
--- a/README.md
+++ b/README.md
@@ -109,7 +109,7 @@ score is the weighted mean of the scorer scores.
 
 | Scorer | Passes when | Key options |
 | --- | --- | --- |
-| `exact-match` | output equals `expected` | `expected`, `caseSensitive`, `trim` |
+| `exact-match` | output equals `expected` | `expected`, `caseSensitive`, `trim`, `collapseWhitespace` |
 | `regex` | output matches a pattern | `pattern`, `flags`, `expectMatch` |
 | `contains` | all substrings present (partial credit) | `value` / `values`, `caseSensitive` |
 | `not-contains` | no banned substring present | `value` / `values`, `caseSensitive` |
diff --git a/src/scorers/exact-match.ts b/src/scorers/exact-match.ts
index 09a757e..5c80aa8 100644
--- a/src/scorers/exact-match.ts
+++ b/src/scorers/exact-match.ts
@@ -9,6 +9,7 @@ import { normalize, result } from "./util.js";
  *  - `expected`: the value to match (falls back to `case.expected`)
  *  - `caseSensitive`: default false
  *  - `trim`: default true
+ *  - `collapseWhitespace`: default true
  */
 export const exactMatchScorer: Scorer = {
   type: "exact-match",
@@ -23,8 +24,9 @@ export const exactMatchScorer: Scorer = {
     }
     const caseSensitive = spec.caseSensitive === true;
     const trim = spec.trim !== false;
-    const a = normalize(ctx.output, { caseSensitive, trim });
-    const b = normalize(expected, { caseSensitive, trim });
+    const collapseWhitespace = spec.collapseWhitespace !== false;
+    const a = normalize(ctx.output, { caseSensitive, trim, collapseWhitespace });
+    const b = normalize(expected, { caseSensitive, trim, collapseWhitespace });
     const passed = a === b;
     return result(spec, {
       score: passed ? 1 : 0,
diff --git a/src/scorers/util.ts b/src/scorers/util.ts
index 8f8aa26..bf570a4 100644
--- a/src/scorers/util.ts
+++ b/src/scorers/util.ts
@@ -29,9 +29,12 @@ export function result(
 }
 
 /** Normalize text for lenient comparisons (trim + collapse whitespace). */
-export function normalize(text: string, opts: { caseSensitive?: boolean; trim?: boolean } = {}): string {
+export function normalize(
+  text: string,
+  opts: { caseSensitive?: boolean; trim?: boolean; collapseWhitespace?: boolean } = {},
+): string {
   let out = text;
   if (opts.trim !== false) out = out.trim();
   if (!opts.caseSensitive) out = out.toLowerCase();
-  return out.replace(/\s+/g, " ");
+  return opts.collapseWhitespace === false ? out : out.replace(/\s+/g, " ");
 }
diff --git a/tests/scorers.test.ts b/tests/scorers.test.ts
index b53c6a2..7aa813d 100644
--- a/tests/scorers.test.ts
+++ b/tests/scorers.test.ts
@@ -49,6 +49,28 @@ describe("exact-match", () => {
     const r = await run(exactMatchScorer, { type: "exact-match" }, ctx("yes", {}, { expected: "yes" }));
     expect(r.passed).toBe(true);
   });
+  it("collapses internal whitespace by default", async () => {
+    const r = await run(
+      exactMatchScorer,
+      { type: "exact-match", expected: "hello world" },
+      ctx("hello\n\nworld"),
+    );
+    expect(r.passed).toBe(true);
+  });
+  it("keeps internal whitespace when collapseWhitespace is false", async () => {
+    const r = await run(
+      exactMatchScorer,
+      {
+        type: "exact-match",
+        expected: "hello\nworld",
+        caseSensitive: true,
+        trim: false,
+        collapseWhitespace: false,
+      },
+      ctx("hello world"),
+    );
+    expect(r.passed).toBe(false);
+  });
 });
 
 describe("regex", () => {