From b6ed9ced6374a38e41b83cacf60bf3d7a5dddadd Mon Sep 17 00:00:00 2001
From: Kelvin Jin <kelvinjin@google.com>
Date: Mon, 10 Dec 2018 14:54:12 -0800
Subject: [PATCH] [node] add trace_events type definitions

---
 types/node/index.d.ts    | 62 ++++++++++++++++++++++++++++++++++++++++
 types/node/node-tests.ts | 14 +++++++++
 2 files changed, 76 insertions(+)

diff --git a/types/node/index.d.ts b/types/node/index.d.ts
index b9edae0587..547a30b84a 100644
--- a/types/node/index.d.ts
+++ b/types/node/index.d.ts
@@ -9008,3 +9008,65 @@ declare module "perf_hooks" {
 
     const performance: Performance;
 }
+
+declare module "trace_events" {
+    /**
+     * The `Tracing` object is used to enable or disable tracing for sets of
+     * categories. Instances are created using the
+     * `trace_events.createTracing()` method.
+     *
+     * When created, the `Tracing` object is disabled. Calling the
+     * `tracing.enable()` method adds the categories to the set of enabled trace
+     * event categories. Calling `tracing.disable()` will remove the categories
+     * from the set of enabled trace event categories.
+     */
+    export interface Tracing {
+        /**
+         * A comma-separated list of the trace event categories covered by this
+         * `Tracing` object.
+         */
+        readonly categories: string;
+
+        /**
+         * Disables this `Tracing` object.
+         *
+         * Only trace event categories _not_ covered by other enabled `Tracing`
+         * objects and _not_ specified by the `--trace-event-categories` flag
+         * will be disabled.
+         */
+        disable(): void;
+
+        /**
+         * Enables this `Tracing` object for the set of categories covered by
+         * the `Tracing` object.
+         */
+        enable(): void;
+
+        /**
+         * `true` only if the `Tracing` object has been enabled.
+         */
+        readonly enabled: boolean;
+    }
+
+    interface CreateTracingOptions {
+        /**
+         * An array of trace category names. Values included in the array are
+         * coerced to a string when possible. An error will be thrown if the
+         * value cannot be coerced.
+         */
+        categories: string[];
+    }
+
+    /**
+     * Creates and returns a Tracing object for the given set of categories.
+     */
+    export function createTracing(options: CreateTracingOptions): Tracing;
+
+    /**
+     * Returns a comma-separated list of all currently-enabled trace event
+     * categories. The current set of enabled trace event categories is
+     * determined by the union of all currently-enabled `Tracing` objects and
+     * any categories enabled using the `--trace-event-categories` flag.
+     */
+    export function getEnabledCategories(): string;
+}
diff --git a/types/node/node-tests.ts b/types/node/node-tests.ts
index c0f80728fc..7bb69e87e4 100644
--- a/types/node/node-tests.ts
+++ b/types/node/node-tests.ts
@@ -30,6 +30,7 @@ import * as async_hooks from "async_hooks";
 import * as http2 from "http2";
 import * as inspector from "inspector";
 import * as perf_hooks from "perf_hooks";
+import * as trace_events from "trace_events";
 import Module = require("module");
 
 // Specifically test buffer module regression.
@@ -4676,6 +4677,19 @@ import * as constants from 'constants';
     }
 }
 
+///////////////////////////////////////////////////////////
+/// Trace Events Tests                                  ///
+///////////////////////////////////////////////////////////
+
+{
+    const enabledCategories: string = trace_events.getEnabledCategories();
+    const tracing: trace_events.Tracing = trace_events.createTracing({ categories: ['node', 'v8'] });
+    const categories: string = tracing.categories;
+    const enabled: boolean = tracing.enabled;
+    tracing.enable();
+    tracing.disable();
+}
+
 ////////////////////////////////////////////////////
 /// module tests : http://nodejs.org/api/modules.html
 ////////////////////////////////////////////////////