Add PostgresError type

lib/backend.js

@@ -1,4 +1,5 @@
-const { errorFields, errors, entries } = require('./types.js')
+const { errors } = require('./errors.js')
+    , { entries, errorFields } = require('./types.js')
 
 const char = (acc, [k, v]) => (acc[k.charCodeAt(0)] = v, acc)
     , N = '\u0000'
@@ -125,8 +126,8 @@ function Backend({
 
   function ErrorResponse(x) {
     backend.query
-      ? (backend.error = errors.generic(parseError(x)))
-      : error(errors.generic(parseError(x)))
+      ? (backend.error = errors.postgres(parseError(x)))
+      : error(errors.postgres(parseError(x)))
   }
 
   /* c8 ignore next 3 */

lib/connection.js

@@ -3,7 +3,8 @@ const tls = require('tls')
 const frontend = require('./frontend.js')
 const Backend = require('./backend.js')
 const Queue = require('./queue.js')
-const { errors, END } = require('./types.js')
+const { END } = require('./types.js')
+const { errors } = require('./errors.js')
 
 module.exports = Connection
 
@@ -99,7 +100,7 @@ function Connection(options = {}) {
   }
 
   function destroy() {
-    error(errors.connection('DESTROYED', options))
+    error(errors.connection('CONNECTION_DESTROYED', options))
     socket.destroy()
   }
 
@@ -224,7 +225,7 @@ function Connection(options = {}) {
 
   function close() {
     connect_timer && (clearTimeout(connect_timer), connect_timer = null)
-    error(errors.connection('CLOSED', options))
+    error(errors.connection('CONNECTION_CLOSED', options))
     statements = {}
     messages = []
     open = ready = false

lib/errors.js

@@ -0,0 +1,53 @@
+class PostgresError extends Error {
+  constructor(x) {
+    super(x.message)
+    this.name = this.constructor.name
+    Object.assign(this, x)
+  }
+}
+
+module.exports.PostgresError = PostgresError
+
+module.exports.errors = {
+  connection,
+  postgres,
+  generic,
+  notSupported
+}
+
+function connection(x, options) {
+  const error = Object.assign(
+    new Error(('write ' + x + ' ' + (options.path || (options.host + ':' + options.port)))),
+    {
+      code: x,
+      errno: x,
+      address: options.path || options.host
+    }, options.path ? {} : { port: options.port }
+  )
+  Error.captureStackTrace(error, connection)
+  return error
+}
+
+function postgres(x) {
+  const error = new PostgresError(x)
+  Error.captureStackTrace(error, postgres)
+  return error
+}
+
+function generic(x) {
+  const error = Object.assign(new Error(x.message), x)
+  Error.captureStackTrace(error, generic)
+  return error
+}
+
+function notSupported(x) {
+  const error = Object.assign(
+    new Error(x + ' (B) is not supported'),
+    {
+      code: 'MESSAGE_NOT_SUPPORTED',
+      name: x
+    }
+  )
+  Error.captureStackTrace(error, notSupported)
+  return error
+}

lib/frontend.js

@@ -1,6 +1,7 @@
 const crypto = require('crypto')
 const bytes = require('./bytes.js')
-const { errors, entries } = require('./types.js')
+const { entries } = require('./types.js')
+const { errors } = require('./errors.js')
 
 const N = String.fromCharCode(0)
 const empty = Buffer.alloc(0)

lib/index.js

@@ -2,6 +2,7 @@ const fs = require('fs')
 const Url = require('url')
 const Connection = require('./connection.js')
 const Queue = require('./queue.js')
+const { errors, PostgresError } = require('./errors.js')
 const {
   mergeUserTypes,
   arraySerializer,
@@ -11,7 +12,6 @@ const {
   entries,
   toCamel,
   toKebab,
-  errors,
   escape,
   types,
   END
@@ -174,7 +174,7 @@ function Postgres(a, b) {
       query.resolve = resolve
       query.reject = reject
       ended !== null
-        ? reject(errors.connection('ENDED', options))
+        ? reject(errors.connection('CONNECTION_ENDED', options))
         : ready
           ? send(connection, query, xs, args)
           : fetchArrayTypes(connection).then(() => send(connection, query, xs, args)).catch(reject)
@@ -270,6 +270,7 @@ function Postgres(a, b) {
   function addTypes(sql, connection) {
     Object.assign(sql, {
       END,
+      PostgresError,
       types: {},
       notify,
       unsafe,

lib/types.js

@@ -1,4 +1,4 @@
-const char = (acc, [k, v]) => (acc[k.charCodeAt(0)] = v, acc)
+const char = module.exports.char = (acc, [k, v]) => (acc[k.charCodeAt(0)] = v, acc)
 const entries = o => Object.keys(o).map(x => [x, o[x]])
 
 // These were the fastest ways to do it in Node.js v12.11.1 (add tests to revise if this changes)
@@ -189,29 +189,6 @@ module.exports.toPascal = x => {
 
 module.exports.toKebab = x => x.replace(/_/g, '-')
 
-module.exports.errors = {
-  connection: (x, options) => Object.assign(
-    new Error(('write CONNECTION_' + x + ' ' + (options.path || (options.host + ':' + options.port)))),
-    {
-      code: 'CONNECTION_' + x,
-      errno: 'CONNECTION_' + x,
-      address: options.path || options.host
-    }, options.path ? {} : { port: options.port }
-  ),
-
-  generic: (x) => Object.assign(
-    new Error(x.message),
-    x
-  ),
-
-  notSupported: x => Object.assign(
-    new Error(x + ' (B) is not supported'),
-    {
-      code: 'MESSAGE_NOT_SUPPORTED'
-    }
-  )
-}
-
 module.exports.errorFields = entries({
   S: 'severity_local',
   V: 'severity',

tests/index.js

@@ -935,7 +935,7 @@ t('Query parameters are not enumerable', async() => [
 ])
 
 t('connect_timeout throws proper error', async() => [
-  'CONNECTION_CONNECT_TIMEOUT',
+  'CONNECT_TIMEOUT',
   await postgres({
     ...options,
     ...login_scram,
@@ -953,11 +953,15 @@ t('requests works after single connect_timeout', async() => {
   })
 
   return [
-    'CONNECTION_CONNECT_TIMEOUT,,1',
+    'CONNECT_TIMEOUT,,1',
     [
       await sql`select 1 as x`.catch(x => x.code),
       await new Promise(r => setTimeout(r, 10)),
       (await sql`select 1 as x`)[0].x
     ].join(',')
   ]
 })
+
+t('Postgres errors are of type PostgresError', async() =>
+  [true, (await sql`bad keyword`.catch(e => e)) instanceof sql.PostgresError]
+)