diff --git a/cli/ops/dispatch_json.rs b/cli/ops/dispatch_json.rs
index 30a3a44333..c3a1c3b3fd 100644
--- a/cli/ops/dispatch_json.rs
+++ b/cli/ops/dispatch_json.rs
@@ -45,14 +45,36 @@ struct AsyncArgs {
   promise_id: Option<u64>,
 }
 
-pub fn json_op<D>(d: D) -> impl OpDispatcher
+/// Like OpDispatcher but with additional json `Value` parameter
+/// and return a result of `JsonOp` instead of `Op`.
+pub trait JsonOpDispatcher {
+  fn dispatch(
+    &self,
+    isolate_state: &mut CoreIsolateState,
+    json: Value,
+    zero_copy: &mut [ZeroCopyBuf],
+  ) -> Result<JsonOp, OpError>;
+}
+
+impl<F> JsonOpDispatcher for F
 where
-  D: Fn(
+  F: Fn(
     &mut CoreIsolateState,
     Value,
     &mut [ZeroCopyBuf],
   ) -> Result<JsonOp, OpError>,
 {
+  fn dispatch(
+    &self,
+    isolate_state: &mut CoreIsolateState,
+    json: Value,
+    zero_copy: &mut [ZeroCopyBuf],
+  ) -> Result<JsonOp, OpError> {
+    self(isolate_state, json, zero_copy)
+  }
+}
+
+pub fn json_op(d: impl JsonOpDispatcher) -> impl OpDispatcher {
   move |isolate_state: &mut CoreIsolateState, zero_copy: &mut [ZeroCopyBuf]| {
     assert!(!zero_copy.is_empty(), "Expected JSON string at position 0");
     let async_args: AsyncArgs = match serde_json::from_slice(&zero_copy[0]) {
@@ -67,7 +89,7 @@ where
 
     let result = serde_json::from_slice(&zero_copy[0])
       .map_err(OpError::from)
-      .and_then(|args| d(isolate_state, args, &mut zero_copy[1..]));
+      .and_then(|args| d.dispatch(isolate_state, args, &mut zero_copy[1..]));
 
     // Convert to Op
     match result {
diff --git a/cli/ops/mod.rs b/cli/ops/mod.rs
index ef8c3bd0f1..331ed4aa19 100644
--- a/cli/ops/mod.rs
+++ b/cli/ops/mod.rs
@@ -4,6 +4,7 @@ mod dispatch_minimal;
 
 pub use dispatch_json::json_op;
 pub use dispatch_json::JsonOp;
+pub use dispatch_json::JsonOpDispatcher;
 pub use dispatch_json::JsonResult;
 pub use dispatch_minimal::minimal_op;
 pub use dispatch_minimal::MinimalOp;
diff --git a/cli/ops/plugin.rs b/cli/ops/plugin.rs
index ba105cff8f..3edcaa962f 100644
--- a/cli/ops/plugin.rs
+++ b/cli/ops/plugin.rs
@@ -3,7 +3,6 @@ use crate::op_error::OpError;
 use crate::ops::dispatch_json::Deserialize;
 use crate::ops::dispatch_json::JsonOp;
 use crate::ops::dispatch_json::Value;
-use crate::ops::json_op;
 use crate::state::State;
 use deno_core::plugin_api;
 use deno_core::CoreIsolate;
@@ -21,10 +20,7 @@ use std::task::Context;
 use std::task::Poll;
 
 pub fn init(i: &mut CoreIsolate, s: &State) {
-  i.register_op(
-    "op_open_plugin",
-    s.core_op(json_op(s.stateful_op2(op_open_plugin))),
-  );
+  i.register_op("op_open_plugin", s.stateful_json_op2(op_open_plugin));
 }
 
 #[derive(Deserialize)]
diff --git a/cli/ops/web_worker.rs b/cli/ops/web_worker.rs
index 553278b074..4a661d2bed 100644
--- a/cli/ops/web_worker.rs
+++ b/cli/ops/web_worker.rs
@@ -2,6 +2,7 @@
 use super::dispatch_json::{JsonOp, Value};
 use crate::op_error::OpError;
 use crate::ops::json_op;
+use crate::ops::JsonOpDispatcher;
 use crate::state::State;
 use crate::web_worker::WebWorkerHandle;
 use crate::worker::WorkerEvent;
@@ -14,11 +15,7 @@ use std::convert::From;
 pub fn web_worker_op<D>(
   sender: mpsc::Sender<WorkerEvent>,
   dispatcher: D,
-) -> impl Fn(
-  &mut CoreIsolateState,
-  Value,
-  &mut [ZeroCopyBuf],
-) -> Result<JsonOp, OpError>
+) -> impl JsonOpDispatcher
 where
   D: Fn(
     &mpsc::Sender<WorkerEvent>,
@@ -36,11 +33,7 @@ pub fn web_worker_op2<D>(
   handle: WebWorkerHandle,
   sender: mpsc::Sender<WorkerEvent>,
   dispatcher: D,
-) -> impl Fn(
-  &mut CoreIsolateState,
-  Value,
-  &mut [ZeroCopyBuf],
-) -> Result<JsonOp, OpError>
+) -> impl JsonOpDispatcher
 where
   D: Fn(
     WebWorkerHandle,
diff --git a/cli/state.rs b/cli/state.rs
index 2d871d74d0..aa78f5c1ae 100644
--- a/cli/state.rs
+++ b/cli/state.rs
@@ -6,6 +6,7 @@ use crate::import_map::ImportMap;
 use crate::metrics::Metrics;
 use crate::op_error::OpError;
 use crate::ops::JsonOp;
+use crate::ops::JsonOpDispatcher;
 use crate::ops::MinimalOp;
 use crate::permissions::Permissions;
 use crate::tsc::TargetLib;
@@ -168,14 +169,7 @@ impl State {
   /// NOTE: This only works with JSON dispatcher.
   /// This is a band-aid for transition to `CoreIsolate.register_op` API as most of our
   /// ops require `state` argument.
-  pub fn stateful_op<D>(
-    &self,
-    dispatcher: D,
-  ) -> impl Fn(
-    &mut deno_core::CoreIsolateState,
-    Value,
-    &mut [ZeroCopyBuf],
-  ) -> Result<JsonOp, OpError>
+  pub fn stateful_op<D>(&self, dispatcher: D) -> impl JsonOpDispatcher
   where
     D: Fn(&State, Value, &mut [ZeroCopyBuf]) -> Result<JsonOp, OpError>,
   {
@@ -186,14 +180,7 @@ impl State {
           -> Result<JsonOp, OpError> { dispatcher(&state, args, zero_copy) }
   }
 
-  pub fn stateful_op2<D>(
-    &self,
-    dispatcher: D,
-  ) -> impl Fn(
-    &mut deno_core::CoreIsolateState,
-    Value,
-    &mut [ZeroCopyBuf],
-  ) -> Result<JsonOp, OpError>
+  pub fn stateful_op2<D>(&self, dispatcher: D) -> impl JsonOpDispatcher
   where
     D: Fn(
       &mut deno_core::CoreIsolateState,
diff --git a/core/ops.rs b/core/ops.rs
index 8aa13936b4..603526dbcb 100644
--- a/core/ops.rs
+++ b/core/ops.rs
@@ -20,11 +20,12 @@ pub enum Op {
   AsyncUnref(OpAsyncFuture),
 }
 
+/// Main type describing Op
 pub trait OpDispatcher {
   fn dispatch(
     &self,
-    isolate: &mut CoreIsolateState,
-    buf: &mut [ZeroCopyBuf],
+    isolate_state: &mut CoreIsolateState,
+    zero_copy: &mut [ZeroCopyBuf],
   ) -> Op;
 }
 
@@ -34,10 +35,10 @@ where
 {
   fn dispatch(
     &self,
-    isolate: &mut CoreIsolateState,
-    buf: &mut [ZeroCopyBuf],
+    isolate_state: &mut CoreIsolateState,
+    zero_copy: &mut [ZeroCopyBuf],
   ) -> Op {
-    self(isolate, buf)
+    self(isolate_state, zero_copy)
   }
 }