Add asObjectBindingsOnly, allowing write to receive only the bindings…

… as object

This allows to pass the format string and args as
is the underlying console when to keep their
special handling, for when using `write` to only
modify the default way the printing to the console
looks rather than writing to an alternate
destination entirely.

Part of #1556

browser.js

@@ -109,6 +109,7 @@ function pino (opts) {
     transmit,
     serialize,
     asObject: opts.browser.asObject,
+    asObjectBindingsOnly: opts.browser.asObjectBindingsOnly,
     formatters: opts.browser.formatters,
     levels,
     timestamp: getTimeFunction(opts),
@@ -317,7 +318,7 @@ function createWrap (self, opts, rootLogger, level) {
         argsIsSerialized = true
       }
       if (opts.asObject || opts.formatters) {
-        write.call(proto, asObject(this, level, args, ts, opts))
+        write.call(proto, ...asObject(this, level, args, ts, opts))
       } else write.apply(proto, args)
 
       if (opts.transmit) {
@@ -347,30 +348,43 @@ function asObject (logger, level, args, ts, opts) {
   const argsCloned = args.slice()
   let msg = argsCloned[0]
   const logObject = {}
-  if (ts) {
-    logObject.time = ts
-  }
-
-  if (levelFormatter) {
-    const formattedLevel = levelFormatter(level, logger.levels.values[level])
-    Object.assign(logObject, formattedLevel)
-  } else {
-    logObject.level = logger.levels.values[level]
-  }
 
   let lvl = (logger._childLevel | 0) + 1
   if (lvl < 1) lvl = 1
-  // deliberate, catching objects, arrays
-  if (msg !== null && typeof msg === 'object') {
-    while (lvl-- && typeof argsCloned[0] === 'object') {
-      Object.assign(logObject, argsCloned.shift())
+
+  if (opts.asObjectBindingsOnly) {
+    if (msg !== null && typeof msg === 'object') {
+      while (lvl-- && typeof argsCloned[0] === 'object') {
+        Object.assign(logObject, argsCloned.shift())
+      }
+    }
+
+    const formattedLogObject = logObjectFormatter(logObject)
+    return [formattedLogObject, ...argsCloned]
+  } else {
+    if (ts) {
+      logObject.time = ts
+    }
+
+    if (levelFormatter) {
+      const formattedLevel = levelFormatter(level, logger.levels.values[level])
+      Object.assign(logObject, formattedLevel)
+    } else {
+      logObject.level = logger.levels.values[level]
     }
-    msg = argsCloned.length ? format(argsCloned.shift(), argsCloned) : undefined
-  } else if (typeof msg === 'string') msg = format(argsCloned.shift(), argsCloned)
-  if (msg !== undefined) logObject[opts.messageKey] = msg
 
-  const formattedLogObject = logObjectFormatter(logObject)
-  return formattedLogObject
+    // deliberate, catching objects, arrays
+    if (msg !== null && typeof msg === 'object') {
+      while (lvl-- && typeof argsCloned[0] === 'object') {
+        Object.assign(logObject, argsCloned.shift())
+      }
+      msg = argsCloned.length ? format(argsCloned.shift(), argsCloned) : undefined
+    } else if (typeof msg === 'string') msg = format(argsCloned.shift(), argsCloned)
+    if (msg !== undefined) logObject[opts.messageKey] = msg
+
+    const formattedLogObject = logObjectFormatter(logObject)
+    return [formattedLogObject]
+  }
 }
 
 function applySerializers (args, serialize, serializers, stdErrSerialize) {