From 50eb7cfbb622559ff4073a3afc3e6ad2799cc7d3 Mon Sep 17 00:00:00 2001
From: Luca Del Puppo <luca@delpuppo.net>
Date: Tue, 8 Aug 2023 17:58:45 +0200
Subject: [PATCH] feat(#1595): improve stream entry types

---
 pino.d.ts                             | 22 ++++++++--------
 test/types/pino-multistream.test-d.ts | 22 +++++++++-------
 test/types/pino.ts                    | 38 ++++++++++++++++++++++++++-
 3 files changed, 60 insertions(+), 22 deletions(-)

diff --git a/pino.d.ts b/pino.d.ts
index b681ee8fe..f6ed8c8ad 100644
--- a/pino.d.ts
+++ b/pino.d.ts
@@ -284,18 +284,18 @@ declare namespace pino {
 
     type DestinationStreamWithMetadata = DestinationStream & ({ [symbols.needsMetadataGsym]?: false } | DestinationStreamHasMetadata);
 
-    interface StreamEntry {
+    interface StreamEntry<TLevel = Level> {
         stream: DestinationStream
-        level?: Level
+        level?: TLevel
     }
 
-    interface MultiStreamRes {
+    interface MultiStreamRes<TOriginLevel = Level> {
         write: (data: any) => void,
-        add: (dest: StreamEntry | DestinationStream) => MultiStreamRes,
+        add: <TLevel = Level>(dest: StreamEntry<TLevel> | DestinationStream) => MultiStreamRes<TOriginLevel & TLevel>,
         flushSync: () => void,
         minLevel: number,
-        streams: StreamEntry[],
-        clone(level: Level): MultiStreamRes,
+        streams: StreamEntry<TOriginLevel>[],
+        clone<TLevel = Level>(level: TLevel): MultiStreamRes<TLevel>,
     }
 
     interface LevelMapping {
@@ -775,10 +775,10 @@ declare namespace pino {
         options: TransportSingleOptions<TransportOptions> | TransportMultiOptions<TransportOptions> | TransportPipelineOptions<TransportOptions>
     ): ThreadStream
 
-    export function multistream(
-        streamsArray: (DestinationStream | StreamEntry)[] | DestinationStream | StreamEntry,
+    export function multistream<TLevel = Level>(
+        streamsArray: (DestinationStream | StreamEntry<TLevel>)[] | DestinationStream | StreamEntry<TLevel>,
         opts?: MultiStreamOptions
-    ): MultiStreamRes
+    ): MultiStreamRes<TLevel>
 }
 
 //// Callable default export
@@ -833,8 +833,8 @@ export interface LogEvent extends pino.LogEvent {}
 export interface LogFn extends pino.LogFn {}
 export interface LoggerOptions extends pino.LoggerOptions {}
 export interface MultiStreamOptions extends pino.MultiStreamOptions {}
-export interface MultiStreamRes extends pino.MultiStreamRes {}
-export interface StreamEntry extends pino.StreamEntry {}
+export interface MultiStreamRes<TLevel = Level> extends pino.MultiStreamRes<TLevel> {}
+export interface StreamEntry<TLevel = Level> extends pino.StreamEntry<TLevel> {}
 export interface TransportBaseOptions extends pino.TransportBaseOptions {}
 export interface TransportMultiOptions extends pino.TransportMultiOptions {}
 export interface TransportPipelineOptions extends pino.TransportPipelineOptions {}
diff --git a/test/types/pino-multistream.test-d.ts b/test/types/pino-multistream.test-d.ts
index 6006f9c53..29f09d7f5 100644
--- a/test/types/pino-multistream.test-d.ts
+++ b/test/types/pino-multistream.test-d.ts
@@ -2,25 +2,27 @@ import { expectType } from 'tsd'
 
 import { createWriteStream } from 'fs'
 
-import pino from '../../pino'
-import { multistream } from "../../pino";
+import pino, { multistream } from '../../pino'
 
 const streams = [
   { stream: process.stdout },
   { stream: createWriteStream('') },
   { level: 'error' as const, stream: process.stderr },
-  { level: 'fatal' as const, stream: createWriteStream('') }
+  { level: 'fatal' as const, stream: process.stderr },
 ]
 
 expectType<pino.MultiStreamRes>(pino.multistream(process.stdout))
 expectType<pino.MultiStreamRes>(pino.multistream([createWriteStream('')]))
-expectType<pino.MultiStreamRes>(pino.multistream({ level: 'error' as const, stream: process.stderr }))
-expectType<pino.MultiStreamRes>(pino.multistream([{ level: 'fatal' as const, stream: createWriteStream('') }]))
+expectType<pino.MultiStreamRes<'error'>>(pino.multistream({ level: 'error' as const, stream: process.stderr }))
+expectType<pino.MultiStreamRes<'fatal'>>(pino.multistream([{ level: 'fatal' as const, stream: createWriteStream('') }]))
+
+expectType<pino.MultiStreamRes<'error' | 'fatal'>>(pino.multistream(streams))
+expectType<pino.MultiStreamRes<'error' | 'fatal'>>(pino.multistream(streams, {}))
+expectType<pino.MultiStreamRes<'error' | 'fatal'>>(pino.multistream(streams, { levels: { 'info': 30 } }))
+expectType<pino.MultiStreamRes<'error' | 'fatal'>>(pino.multistream(streams, { dedupe: true }))
+expectType<pino.MultiStreamRes<'error' | 'fatal'>>(pino.multistream(streams[0]).add(streams[1]))
+expectType<pino.MultiStreamRes<'error' | 'fatal'>>(multistream(streams))
+expectType<pino.MultiStreamRes<'error'>>(multistream(streams).clone('error'))
 
-expectType<pino.MultiStreamRes>(pino.multistream(streams))
-expectType<pino.MultiStreamRes>(pino.multistream(streams, {}))
-expectType<pino.MultiStreamRes>(pino.multistream(streams, { levels: { 'info': 30 } }))
-expectType<pino.MultiStreamRes>(pino.multistream(streams, { dedupe: true }))
-expectType<pino.MultiStreamRes>(pino.multistream(streams[0]).add(streams[1]))
 
 expectType<pino.MultiStreamRes>(multistream(process.stdout));
diff --git a/test/types/pino.ts b/test/types/pino.ts
index 5ac2d936e..c1cf8c0f6 100644
--- a/test/types/pino.ts
+++ b/test/types/pino.ts
@@ -1,6 +1,7 @@
-import { pino } from '../../pino'
+import { StreamEntry, pino } from '../../pino'
 import { join } from 'path'
 import { tmpdir } from 'os'
+import pinoPretty from 'pino-pretty'
 
 const destination = join(
     tmpdir(),
@@ -40,3 +41,38 @@ const transports = pino.transport({targets: [
 ]})
 const loggerMulti = pino(transports)
 loggerMulti.info('test2')
+
+// custom levels
+
+const customLevels = {
+    debug   : 1,
+    info    : 2,
+    network : 3,
+    error   : 4,
+};
+
+type CustomLevels = keyof typeof customLevels;
+
+const pinoOpts = {
+    level: 'debug',
+    useOnlyCustomLevels: true,
+    customLevels: customLevels,
+};
+
+const multistreamOpts = {
+    dedupe: true,
+    levels: customLevels
+};
+
+const streams: StreamEntry<CustomLevels>[] = [
+    { level : 'debug',   stream : pinoPretty() },
+    { level : 'info',    stream : pinoPretty() },
+    { level : 'network', stream : pinoPretty() },
+    { level : 'error',   stream : pinoPretty() },
+];
+
+const loggerCustomLevel = pino(pinoOpts, pino.multistream(streams, multistreamOpts));
+loggerCustomLevel.debug('test3')
+loggerCustomLevel.info('test4')
+loggerCustomLevel.error('test5')
+loggerCustomLevel.network('test6')