feat(console): print proxy details (#7139)

cli/dts/lib.deno.ns.d.ts

@@ -1952,6 +1952,8 @@ declare namespace Deno {
     compact?: boolean;
     /** The maximum number of iterable entries to print. Defaults to 100. */
     iterableLimit?: number;
+    /** Show a Proxy's target and handler. Defaults to false. */
+    showProxy?: boolean;
   }
 
   /** Converts the input into a string that has the same format as printed by

cli/rt/02_console.js

@@ -154,6 +154,7 @@
     trailingComma: false,
     compact: true,
     iterableLimit: 100,
+    showProxy: false,
   };
 
   const DEFAULT_INDENT = "  "; // Default indent string
@@ -400,6 +401,13 @@
     level,
     inspectOptions,
   ) {
+    const proxyDetails = Deno.core.getProxyDetails(value);
+    if (proxyDetails != null) {
+      return inspectOptions.showProxy
+        ? inspectProxy(proxyDetails, ctx, level, inspectOptions)
+        : inspectValue(proxyDetails[0], ctx, level, inspectOptions);
+    }
+
     switch (typeof value) {
       case "string":
         return value;
@@ -657,7 +665,16 @@
     return `Promise { ${str} }`;
   }
 
-  // TODO: Proxy
+  function inspectProxy(
+    targetAndHandler,
+    ctx,
+    level,
+    inspectOptions,
+  ) {
+    return `Proxy ${
+      inspectArray(targetAndHandler, ctx, level, inspectOptions)
+    }`;
+  }
 
   function inspectRawObject(
     value,

cli/tests/unit/console_test.ts

@@ -1367,3 +1367,50 @@ unitTest(function inspectIterableLimit(): void {
     `Map { "a" => 1, "b" => 2, ... 1 more items }`,
   );
 });
+
+unitTest(function inspectProxy(): void {
+  assertEquals(
+    Deno.inspect(
+      new Proxy([1, 2, 3], { get(): void {} }),
+    ),
+    "[ 1, 2, 3 ]",
+  );
+  assertEquals(
+    Deno.inspect(
+      new Proxy({ key: "value" }, { get(): void {} }),
+    ),
+    `{ key: "value" }`,
+  );
+  assertEquals(
+    Deno.inspect(new Proxy([1, 2, 3], { get(): void {} }), { showProxy: true }),
+    "Proxy [ [ 1, 2, 3 ], { get: [Function: get] } ]",
+  );
+  assertEquals(
+    Deno.inspect(
+      new Proxy({ a: 1 }, {
+        set(): boolean {
+          return false;
+        },
+      }),
+      { showProxy: true },
+    ),
+    "Proxy [ { a: 1 }, { set: [Function: set] } ]",
+  );
+  assertEquals(
+    Deno.inspect(
+      new Proxy([1, 2, 3, 4, 5, 6, 7], { get(): void {} }),
+      { showProxy: true },
+    ),
+    `Proxy [ [
+    1, 2, 3, 4,
+    5, 6, 7
+  ], { get: [Function: get] } ]`,
+  );
+  assertEquals(
+    Deno.inspect(
+      new Proxy(function fn() {}, { get(): void {} }),
+      { showProxy: true },
+    ),
+    "Proxy [ [Function: fn], { get: [Function: get] } ]",
+  );
+});

core/bindings.rs

@@ -50,7 +50,10 @@ lazy_static! {
       },
       v8::ExternalReference {
         function: get_promise_details.map_fn_to()
-      }
+      },
+      v8::ExternalReference {
+        function: get_proxy_details.map_fn_to()
+      },
     ]);
 }
 
@@ -181,6 +184,18 @@ pub fn initialize_context<'s>(
     get_promise_details_val.into(),
   );
 
+  let get_proxy_details_key =
+    v8::String::new(scope, "getProxyDetails").unwrap();
+  let get_proxy_details_tmpl =
+    v8::FunctionTemplate::new(scope, get_proxy_details);
+  let get_proxy_details_val =
+    get_proxy_details_tmpl.get_function(scope).unwrap();
+  core_val.set(
+    scope,
+    get_proxy_details_key.into(),
+    get_proxy_details_val.into(),
+  );
+
   let shared_key = v8::String::new(scope, "shared").unwrap();
   core_val.set_accessor(scope, shared_key.into(), shared_getter);
 
@@ -797,6 +812,50 @@ fn get_promise_details(
   }
 }
 
+// Based on https://github.com/nodejs/node/blob/1e470510ff74391d7d4ec382909ea8960d2d2fbc/src/node_util.cc
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+fn get_proxy_details(
+  scope: &mut v8::HandleScope,
+  args: v8::FunctionCallbackArguments,
+  mut rv: v8::ReturnValue,
+) {
+  // Return undefined if it's not a proxy.
+  let proxy = match v8::Local::<v8::Proxy>::try_from(args.get(0)) {
+    Ok(val) => val,
+    Err(_) => {
+      return;
+    }
+  };
+
+  let proxy_details = v8::Array::new(scope, 2);
+  let js_zero = v8::Integer::new(scope, 0);
+  let js_one = v8::Integer::new(scope, 1);
+  let target = proxy.get_target(scope);
+  let handler = proxy.get_handler(scope);
+  proxy_details.set(scope, js_zero.into(), target);
+  proxy_details.set(scope, js_one.into(), handler);
+  rv.set(proxy_details.into());
+}
+
 fn throw_type_error<'s>(
   scope: &mut v8::HandleScope<'s>,
   message: impl AsRef<str>,