Refactor the mixing logic (#1335)

pinojs · Feb 15, 2022 · 3053a99 · 3053a99
1 parent dbde8b7
commit 3053a99
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Showing 2 changed files with 14 additions and 5 deletions.
diff --git a/lib/proto.js b/lib/proto.js
@@ -164,19 +164,23 @@ function write (_obj, msg, num) {
   let obj
 
   if (_obj === undefined || _obj === null) {
-    obj = mixin ? mixin({}) : {}
+    obj = {}
   } else if (_obj instanceof Error) {
-    obj = Object.assign(mixin ? mixin({}) : {}, { err: _obj })
+    obj = { err: _obj }
     if (msg === undefined) {
       msg = _obj.message
     }
   } else {
-    obj = Object.assign(mixin ? mixin({}) : {}, _obj)
+    obj = _obj
     if (msg === undefined && _obj.err) {
       msg = _obj.err.message
     }
   }
 
+  if (mixin) {
+    obj = Object.assign(mixin(obj), obj)
+  }
+
   const s = this[asJsonSym](obj, msg, num, t)
 
   const stream = this[streamSym]

diff --git a/test/mixin.test.js b/test/mixin.test.js
@@ -102,12 +102,16 @@ test('mixin not a function', async ({ throws }) => {
   })
 })
 
-test('mixin can use context', async ({ ok }) => {
+test('mixin can use context', async ({ ok, same }) => {
   const stream = sink()
   const instance = pino({
     mixin (context) {
       ok(context !== null, 'context should be defined')
       ok(context !== undefined, 'context should be defined')
+      same(context, {
+        message: '123',
+        stack: 'stack'
+      })
       return Object.assign({
         error: context.message,
         stack: context.stack
@@ -121,12 +125,13 @@ test('mixin can use context', async ({ ok }) => {
   }, 'test')
 })
 
-test('mixin works without context', async ({ ok }) => {
+test('mixin works without context', async ({ ok, same }) => {
   const stream = sink()
   const instance = pino({
     mixin (context) {
       ok(context !== null, 'context is still defined w/o passing mergeObject')
       ok(context !== undefined, 'context is still defined w/o passing mergeObject')
+      same(context, {})
       return {
         something: true
       }