From 5262ee0e3315ad82fd7730d9776106aac3435037 Mon Sep 17 00:00:00 2001
From: Nigro Simone <nigro.simone@gmail.com>
Date: Sat, 18 Jan 2025 20:18:58 +0100
Subject: [PATCH 1/3] feat: format dirty

---
 README.md          | 22 ++++++++++++++++++++--
 benchmark/bench.js | 16 ++++++++++++++++
 index.js           |  2 ++
 lib/serializer.js  |  7 ++++++-
 test/basic.test.js |  6 ++++++
 5 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 4bc8f0bd..4e873d83 100644
--- a/README.md
+++ b/README.md
@@ -641,8 +641,26 @@ const stringify = fastJson({
   type: 'object',
   properties: {
     'code': {
-	    type: 'string',
-	    format 'unsafe'
+      type: 'string',
+      format: 'unsafe'
+    }
+  }
+})
+```
+
+<a name="dirty"></a>
+#### Dirty string
+String known to contain non-printable characters or surrogate pairs.
+
+Example:
+```javascript
+const stringify = fastJson({
+  title: 'Example Schema',
+  type: 'object',
+  properties: {
+    'code': {
+      type: 'string',
+      format: 'dirty'
     }
   }
 })
diff --git a/benchmark/bench.js b/benchmark/bench.js
index acb87b94..770843fd 100644
--- a/benchmark/bench.js
+++ b/benchmark/bench.js
@@ -55,6 +55,14 @@ const benchmarks = [
     },
     input: 'hello world'
   },
+  {
+    name: 'dirty short string',
+    schema: {
+      type: 'string',
+      format: 'dirty'
+    },
+    input: 'hello\nworld'
+  },
   {
     name: 'short string with double quote',
     schema: {
@@ -92,6 +100,14 @@ const benchmarks = [
     },
     input: longString
   },
+  {
+    name: 'dirty long string',
+    schema: {
+      type: 'string',
+      format: 'dirty'
+    },
+    input: longString + '\n'
+  },
   {
     name: 'number',
     schema: {
diff --git a/index.js b/index.js
index 2390c28a..304b67a2 100644
--- a/index.js
+++ b/index.js
@@ -736,6 +736,8 @@ function buildSingleTypeSerializer (context, location, input) {
         return `json += serializer.asTime(${input})`
       } else if (schema.format === 'unsafe') {
         return `json += serializer.asUnsafeString(${input})`
+      } else if (schema.format === 'dirty') {
+        return `json += JSON.stringify(${input})`
       } else {
         return `
         if (typeof ${input} !== 'string') {
diff --git a/lib/serializer.js b/lib/serializer.js
index df81960e..b5f60bf1 100644
--- a/lib/serializer.js
+++ b/lib/serializer.js
@@ -2,6 +2,7 @@
 
 // eslint-disable-next-line
 const STR_ESCAPE = /[\u0000-\u001f\u0022\u005c\ud800-\udfff]/
+const MAGIC_NUMBER = 42
 
 module.exports = class Serializer {
   constructor (options) {
@@ -92,7 +93,7 @@ module.exports = class Serializer {
 
   asString (str) {
     const len = str.length
-    if (len < 42) {
+    if (len < MAGIC_NUMBER) {
       // magically escape strings for json
       // relying on their charCodeAt
       // everything below 32 needs JSON.stringify()
@@ -129,6 +130,10 @@ module.exports = class Serializer {
     return '"' + str + '"'
   }
 
+  asDirty (str) {
+    return JSON.stringify(str)
+  }
+
   getState () {
     return this._options
   }
diff --git a/test/basic.test.js b/test/basic.test.js
index 754f4489..0c3a6c0b 100644
--- a/test/basic.test.js
+++ b/test/basic.test.js
@@ -24,6 +24,12 @@ buildTest({
   format: 'unsafe'
 }, 'hello world')
 
+buildTest({
+  title: 'string',
+  type: 'string',
+  format: 'dirty'
+}, 'hello\nworld')
+
 buildTest({
   title: 'basic',
   type: 'object',

From 2fec47619e6d19ed46686c420028021541b2b8a2 Mon Sep 17 00:00:00 2001
From: Nigro Simone <nigro.simone@gmail.com>
Date: Sat, 18 Jan 2025 20:35:11 +0100
Subject: [PATCH 2/3] fix: revert magic number

---
 lib/serializer.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/serializer.js b/lib/serializer.js
index b5f60bf1..c5950bda 100644
--- a/lib/serializer.js
+++ b/lib/serializer.js
@@ -2,7 +2,6 @@
 
 // eslint-disable-next-line
 const STR_ESCAPE = /[\u0000-\u001f\u0022\u005c\ud800-\udfff]/
-const MAGIC_NUMBER = 42
 
 module.exports = class Serializer {
   constructor (options) {
@@ -93,7 +92,7 @@ module.exports = class Serializer {
 
   asString (str) {
     const len = str.length
-    if (len < MAGIC_NUMBER) {
+    if (len < 42) {
       // magically escape strings for json
       // relying on their charCodeAt
       // everything below 32 needs JSON.stringify()

From 7a2a31add85286c7019634daaf78f53096b403d6 Mon Sep 17 00:00:00 2001
From: Nigro Simone <nigro.simone@gmail.com>
Date: Sat, 18 Jan 2025 20:43:19 +0100
Subject: [PATCH 3/3] fix: call serializer.asDirty

---
 index.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/index.js b/index.js
index 304b67a2..c0d77ca9 100644
--- a/index.js
+++ b/index.js
@@ -737,7 +737,7 @@ function buildSingleTypeSerializer (context, location, input) {
       } else if (schema.format === 'unsafe') {
         return `json += serializer.asUnsafeString(${input})`
       } else if (schema.format === 'dirty') {
-        return `json += JSON.stringify(${input})`
+        return `json += serializer.asDirty(${input})`
       } else {
         return `
         if (typeof ${input} !== 'string') {