✨ callback is always a function

lib/batch.js

@@ -66,7 +66,7 @@ Batch.prototype.write = function (callback) {
     this.batch.write(function (err) {
       if (err) { return dispatchError(levelup, new WriteError(err), callback) }
       levelup.emit('batch', ops)
-      if (callback) { callback() }
+      callback()
     })
   } catch (err) {
     throw new WriteError(err)

lib/levelup.js

@@ -73,12 +73,12 @@ LevelUP.prototype.open = function (callback) {
   if (!callback) [ callback, promise ] = promisify()
 
   if (this.isOpen()) {
-    if (callback) { process.nextTick(function () { callback(null, self) }) }
+    process.nextTick(callback, null, self)
     return promise
   }
 
   if (this._isOpening()) {
-    if (callback) this.once('open', function () { callback(null, self) })
+    this.once('open', function () { callback(null, self) })
     return promise
   }
 
@@ -89,7 +89,7 @@ LevelUP.prototype.open = function (callback) {
       return dispatchError(self, new OpenError(err), callback)
     }
     self.db = self._db
-    if (callback) { callback(null, self) }
+    callback(null, self)
     self.emit('open')
     self.emit('ready')
   })
@@ -106,13 +106,13 @@ LevelUP.prototype.close = function (callback) {
   if (this.isOpen()) {
     this.db.close(function () {
       self.emit('closed')
-      if (callback) { callback.apply(null, arguments) }
+      callback.apply(null, arguments)
     })
     this.emit('closing')
     this.db = new DeferredLevelDOWN(this._db)
-  } else if (this.isClosed() && callback) {
+  } else if (this.isClosed()) {
     process.nextTick(callback)
-  } else if (this.db.status === 'closing' && callback) {
+  } else if (this.db.status === 'closing') {
     this.once('closed', callback)
   } else if (this._isOpening()) {
     this.once('open', function () {
@@ -160,7 +160,7 @@ LevelUP.prototype.get = function (key, options, callback) {
       }
       return dispatchError(self, err, callback)
     }
-    if (callback) { callback(null, value) }
+    callback(null, value)
   })
 
   return promise
@@ -187,7 +187,7 @@ LevelUP.prototype.put = function (key, value, options, callback) {
       return dispatchError(self, new WriteError(err), callback)
     }
     self.emit('put', key, value)
-    if (callback) { callback() }
+    callback()
   })
 
   return promise
@@ -214,7 +214,7 @@ LevelUP.prototype.del = function (key, options, callback) {
       return dispatchError(self, new WriteError(err), callback)
     }
     self.emit('del', key)
-    if (callback) { callback() }
+    callback()
   })
 
   return promise
@@ -250,7 +250,7 @@ LevelUP.prototype.batch = function (arr, options, callback) {
       return dispatchError(self, new WriteError(err), callback)
     }
     self.emit('batch', arr)
-    if (callback) { callback() }
+    callback()
   })
 
   return promise