fix(csv-to-pg): add preserveEmptyStrings option, default true

packages/csv-to-pg/__tests__/__snapshots__/export.test.ts.snap

@@ -94,6 +94,36 @@ exports[`test case test case parser 1`] = `
   ('450e3b3b-b68d-4abc-990c-65cb8a1dcdb4', '450e3b3b-b68d-4abc-990c-65cb8a1dcdb4', '450e3b3b-b68d-4abc-990c-65cb8a1dcdb4', 'name here', 'description');"
 `;
 
+exports[`test case text fields convert empty strings to NULL when preserveEmptyStrings is false 1`] = `
+"INSERT INTO services_public.webauthn_settings (
+  id,
+  database_id,
+  rp_id,
+  rp_name
+) VALUES
+  ('450e3b3b-b68d-4abc-990c-65cb8a1dcdb4', '550e8400-e29b-41d4-a716-446655440000', NULL, NULL);"
+`;
+
+exports[`test case text fields preserve empty strings by default 1`] = `
+"INSERT INTO services_public.webauthn_settings (
+  id,
+  database_id,
+  rp_id,
+  rp_name
+) VALUES
+  ('450e3b3b-b68d-4abc-990c-65cb8a1dcdb4', '550e8400-e29b-41d4-a716-446655440000', '', '');"
+`;
+
+exports[`test case text fields with null values produce NULL 1`] = `
+"INSERT INTO services_public.webauthn_settings (
+  id,
+  database_id,
+  rp_id,
+  rp_name
+) VALUES
+  ('450e3b3b-b68d-4abc-990c-65cb8a1dcdb4', '550e8400-e29b-41d4-a716-446655440000', NULL, NULL);"
+`;
+
 exports[`test case uuid[] arrays 1`] = `
 "INSERT INTO metaschema_public.primary_key_constraint (
   id,

packages/csv-to-pg/__tests__/export.test.ts

@@ -276,6 +276,88 @@ it('empty array fields emit empty array literal', async () => {
   expect(sql).toMatchSnapshot();
 });
 
+it('text fields preserve empty strings by default', async () => {
+  const parser = new Parser({
+    schema: 'services_public',
+    singleStmts: true,
+    table: 'webauthn_settings',
+    fields: {
+      id: 'uuid',
+      database_id: 'uuid',
+      rp_id: 'text',
+      rp_name: 'text'
+    }
+  });
+
+  const sql = await parser.parse([
+    {
+      id: '450e3b3b-b68d-4abc-990c-65cb8a1dcdb4',
+      database_id: '550e8400-e29b-41d4-a716-446655440000',
+      rp_id: '',
+      rp_name: ''
+    }
+  ]);
+
+  // Default: empty strings are preserved as ''
+  expect(sql).not.toContain('NULL');
+  expect(sql).toMatchSnapshot();
+});
+
+it('text fields convert empty strings to NULL when preserveEmptyStrings is false', async () => {
+  const parser = new Parser({
+    schema: 'services_public',
+    singleStmts: true,
+    table: 'webauthn_settings',
+    preserveEmptyStrings: false,
+    fields: {
+      id: 'uuid',
+      database_id: 'uuid',
+      rp_id: 'text',
+      rp_name: 'text'
+    }
+  });
+
+  const sql = await parser.parse([
+    {
+      id: '450e3b3b-b68d-4abc-990c-65cb8a1dcdb4',
+      database_id: '550e8400-e29b-41d4-a716-446655440000',
+      rp_id: '',
+      rp_name: ''
+    }
+  ]);
+
+  // Opt-in: empty strings treated as NULL (CSV convention)
+  expect(sql).toContain('NULL');
+  expect(sql).toMatchSnapshot();
+});
+
+it('text fields with null values produce NULL', async () => {
+  const parser = new Parser({
+    schema: 'services_public',
+    singleStmts: true,
+    table: 'webauthn_settings',
+    fields: {
+      id: 'uuid',
+      database_id: 'uuid',
+      rp_id: 'text',
+      rp_name: 'text'
+    }
+  });
+
+  const sql = await parser.parse([
+    {
+      id: '450e3b3b-b68d-4abc-990c-65cb8a1dcdb4',
+      database_id: '550e8400-e29b-41d4-a716-446655440000',
+      rp_id: null,
+      rp_name: null
+    }
+  ]);
+
+  // Actual null values should still produce NULL
+  expect(sql).toContain('NULL');
+  expect(sql).toMatchSnapshot();
+});
+
 it('interval type with string value', async () => {
   const parser = new Parser({
     schema: 'metaschema_modules_public',

packages/csv-to-pg/src/parse.ts

@@ -239,7 +239,7 @@ const makeNullOrThrow = (fieldName: string, rawValue: unknown, type: string, req
 
 // type (int, text, etc)
 // from Array of keys that map to records found (e.g., ['lon', 'lat'])
-const getCoercionFunc = (type: string, from: string[], opts: FieldOptions, fieldName: string): CoercionFunc => {
+const getCoercionFunc = (type: string, from: string[], opts: FieldOptions, fieldName: string, globalOpts?: GlobalParseOptions): CoercionFunc => {
   const parseFn = opts.parse || identity;
   const required = opts.required || false;
 
@@ -436,7 +436,9 @@ const getCoercionFunc = (type: string, from: string[], opts: FieldOptions, field
     case 'text':
       return (record: Record<string, unknown>): Node => {
         const rawValue = record[from[0]];
-        const value = parseFn(cleanseEmptyStrings(rawValue));
+        const preserve = globalOpts?.preserveEmptyStrings !== false;
+        const cleansed = preserve ? rawValue : cleanseEmptyStrings(rawValue);
+        const value = parseFn(cleansed);
         if (isEmpty(value)) {
           return makeNullOrThrow(fieldName, rawValue, type, required, 'value is empty or null');
         }
@@ -525,15 +527,23 @@ interface ConfigFields {
   [key: string]: string | FieldOptions;
 }
 
+export interface GlobalParseOptions {
+  preserveEmptyStrings?: boolean;
+}
+
 interface Config {
   fields: ConfigFields;
+  preserveEmptyStrings?: boolean;
 }
 
 interface TypesMap {
   [key: string]: CoercionFunc;
 }
 
 export const parseTypes = (config: Config): TypesMap => {
+  const globalOpts: GlobalParseOptions = {
+    preserveEmptyStrings: config.preserveEmptyStrings
+  };
   return Object.entries(config.fields).reduce<TypesMap>((m, v) => {
     let [key, value] = v;
     let type: string;
@@ -552,7 +562,7 @@ export const parseTypes = (config: Config): TypesMap => {
       type = value.type!;
       from = getFromValue(value.from || key);
     }
-    m[key] = getCoercionFunc(type, from, value, key);
+    m[key] = getCoercionFunc(type, from, value, key, globalOpts);
     return m;
   }, {});
 };

packages/csv-to-pg/src/parser.ts

@@ -15,6 +15,7 @@ interface ParserConfig {
   input?: string;
   debug?: boolean;
   fields: Record<string, unknown>;
+  preserveEmptyStrings?: boolean;
 }
 
 interface CsvOptions {