Support transform.undefined - fixes porsager#314

Author: porsager

src/index.js

@@ -397,7 +397,7 @@ function parseOptions(a, b) {
     onnotify        : o.onnotify,
     onclose         : o.onclose,
     onparameter     : o.onparameter,
-    transform       : parseTransform(o.transform || {}),
+    transform       : parseTransform(o.transform || { undefined: undefined }),
     connection      : Object.assign({ application_name: 'postgres.js' }, o.connection),
     target_session_attrs: tsa(o, url, env),
     debug           : o.debug,
@@ -429,6 +429,7 @@ function max_lifetime() {
 
 function parseTransform(x) {
   return {
+    undefined: x.undefined,
     column: {
       from: typeof x.column === 'function' ? x.column : x.column && x.column.from,
       to: x.column && x.column.to

src/types.js

@@ -73,10 +73,16 @@ export class Builder extends NotTagged {
   }
 }
 
-export function handleValue(x, parameters, types) {
-  const value = x instanceof Parameter ? x.value : x
-  if (value === undefined)
-    throw Errors.generic('UNDEFINED_VALUE', 'Undefined values are not allowed')
+export function handleValue(x, parameters, types, options) {
+  let value = x instanceof Parameter ? x.value : x
+  if (value === undefined) {
+    x instanceof Parameter
+      ? x.value = options.transform.undefined
+      : value = x = options.transform.undefined
+
+    if (value === undefined)
+      throw Errors.generic('UNDEFINED_VALUE', 'Undefined values are not allowed')
+  }
 
   return '$' + (types.push(
     x instanceof Parameter

tests/index.js

@@ -319,6 +319,16 @@ t('Undefined values throws', async() => {
   return ['UNDEFINED_VALUE', error]
 })
 
+t('Transform undefined', async() => {
+  const sql = postgres({ transform: { undefined: null } })
+  return [null, (await sql`select ${ undefined } as x`)[0].x]
+})
+
+t('Transform undefined in array', async() => {
+  const sql = postgres({ transform: { undefined: null } })
+  return [null, (await sql`select * from (values ${ sql([undefined, undefined]) }) as x(x, y)`)[0].y]
+})
+
 t('Null sets to null', async() =>
   [null, (await sql`select ${ null } as x`)[0].x]
 )