Fix null json array transform error

Author: Eprince-hub

src/types.js

@@ -39,6 +39,10 @@ export const types = {
   }
 }
 
+const allowList = {
+  object: typeof Object
+}
+
 class NotTagged { then() { notTagged() } catch() { notTagged() } finally() { notTagged() }}
 
 export class Identifier extends NotTagged {
@@ -325,7 +329,7 @@ export const fromKebab = x => x.replace(/-/g, '_')
 
 function createJsonTransform(fn) {
   return function jsonTransform(x, column) {
-    return column.type === 114 || column.type === 3802
+    return (x && typeof x in allowList) && (column.type === 114 || column.type === 3802)
       ? Array.isArray(x)
         ? x.map(x => jsonTransform(x, column))
         : Object.entries(x).reduce((acc, [k, v]) => Object.assign(acc, { [fn(k)]: v }), {})

tests/index.js

@@ -612,6 +612,14 @@ t('Transform nested json in arrays', async() => {
   return ['aBcD', (await sql`select '[{"a_b":1},{"c_d":2}]'::jsonb as x`)[0].x.map(Object.keys).join('')]
 })
 
+t('Transform null json in arrays', async() => {
+  const sql = postgres({
+    ...options,
+    transform: postgres.camel
+  })
+  return [null, (await sql`select '[{"a_b":null},{"c_d":null}]'::jsonb as x`)[0].x.map(Object.keys).join('')]
+})
+
 t('unsafe', async() => {
   await sql`create table test (x int)`
   return [1, (await sql.unsafe('insert into test values ($1) returning *', [1]))[0].x, await sql`drop table test`]