Patch Drizzle MySQL JSON

When using Drizzle with MySQL, the JSON data type is not parsed correctly.

Until drizzle-orm/PR#4224 is merged, you can apply the following patch to fix the issue.

Patch file

Create the file patches/drizzle-orm.patch:

diff --git a/mysql-core/columns/json.cjs b/mysql-core/columns/json.cjs
index f22ca95afbf8493eacf93a2036d950cbe6a61876..72fa9b46dc18ce763fef9b3d4a0986fe6094b0df 100644
--- a/mysql-core/columns/json.cjs
+++ b/mysql-core/columns/json.cjs
@@ -43,6 +43,16 @@ class MySqlJson extends import_common.MySqlColumn {
   mapToDriverValue(value) {
     return JSON.stringify(value);
   }
+  mapFromDriverValue(value) {
+       if (typeof value === 'string') {
+           try {
+               return JSON.parse(value);
+           } catch {
+               return value;
+           }
+       }
+       return value;
+   }
 }
 function json(name) {
   return new MySqlJsonBuilder(name ?? "");
diff --git a/mysql-core/columns/json.js b/mysql-core/columns/json.js
index db2a1c5c600af80027b70ef6b35b18eacfe41f64..0ea361998b994e352ede4f82071333c8c69a0703 100644
--- a/mysql-core/columns/json.js
+++ b/mysql-core/columns/json.js
@@ -18,6 +18,16 @@ class MySqlJson extends MySqlColumn {
   mapToDriverValue(value) {
     return JSON.stringify(value);
   }
+  mapFromDriverValue(value) {
+       if (typeof value === 'string') {
+           try {
+               return JSON.parse(value);
+           } catch {
+               return value;
+           }
+       }
+       return value;
+   }
 }
 function json(name) {
   return new MySqlJsonBuilder(name ?? "");

Register the patch

Add the following to your package.json:

 "pnpm": {
    "patchedDependencies": {
      "drizzle-orm": "patches/drizzle-orm.patch"
    }
  },