From 6d1cfec83e8ca19331aa114fe7f85b4ea5a179f0 Mon Sep 17 00:00:00 2001
From: Noemi <noemi@appsignal.com>
Date: Mon, 10 Jan 2022 22:27:39 +0100
Subject: [PATCH] Implement unregister method for probes

Before this change, it was possible to disable a probe by
registering an empty probe with the same name, but this is neither
obvious nor documented. This commit adds a `probes.unregister()`
method that removes a probe in a more explicit manner.
---
 .../implement-unregister-method-for-probes.md       |  7 +++++++
 packages/nodejs/src/__tests__/probes.test.ts        | 10 ++++++++++
 packages/nodejs/src/interfaces/probes.ts            |  5 +++++
 packages/nodejs/src/probes/index.ts                 | 13 +++++++++++++
 4 files changed, 35 insertions(+)
 create mode 100644 packages/nodejs/.changesets/implement-unregister-method-for-probes.md

diff --git a/packages/nodejs/.changesets/implement-unregister-method-for-probes.md b/packages/nodejs/.changesets/implement-unregister-method-for-probes.md
new file mode 100644
index 00000000..ac0bbf7f
--- /dev/null
+++ b/packages/nodejs/.changesets/implement-unregister-method-for-probes.md
@@ -0,0 +1,7 @@
+---
+bump: "patch"
+type: "add"
+---
+
+Implement unregister method for probes. You can now call the
+`probes.unregister(name)` method to unregister a probe by name.
diff --git a/packages/nodejs/src/__tests__/probes.test.ts b/packages/nodejs/src/__tests__/probes.test.ts
index 402d6b78..ea497567 100644
--- a/packages/nodejs/src/__tests__/probes.test.ts
+++ b/packages/nodejs/src/__tests__/probes.test.ts
@@ -21,6 +21,16 @@ describe("Probes", () => {
     probes.register("test_metric", fn)
     jest.runOnlyPendingTimers()
     expect(fn).toHaveBeenCalled()
+    expect(probes.count).toEqual(1)
+  })
+
+  it("unregisters a probe", () => {
+    const fn = jest.fn()
+    probes.register("test_metric", fn)
+    probes.unregister("test_metric")
+    jest.runOnlyPendingTimers()
+    expect(fn).not.toHaveBeenCalled()
+    expect(probes.count).toEqual(0)
   })
 
   describe("v8 probe", () => {
diff --git a/packages/nodejs/src/interfaces/probes.ts b/packages/nodejs/src/interfaces/probes.ts
index f9e07826..2eaecd60 100644
--- a/packages/nodejs/src/interfaces/probes.ts
+++ b/packages/nodejs/src/interfaces/probes.ts
@@ -13,6 +13,11 @@ export interface Probes {
    */
   register(name: string, fn: () => void): this
 
+  /**
+   * Unregisters an existing minutely probe.
+   */
+  unregister(name: string): this
+
   /**
    * Unregisters all probes and clears the timers.
    */
diff --git a/packages/nodejs/src/probes/index.ts b/packages/nodejs/src/probes/index.ts
index 6d8dab13..5af87b59 100644
--- a/packages/nodejs/src/probes/index.ts
+++ b/packages/nodejs/src/probes/index.ts
@@ -31,12 +31,25 @@ export class BaseProbes extends EventEmitter implements Probes {
     return this.on(name, fn)
   }
 
+  public unregister(name: string): this {
+    const timer = this.#timers.get(name)
+
+    if (typeof timer !== "undefined") {
+      clearInterval(timer)
+      this.#timers.delete(name)
+      this.removeAllListeners(name)
+    }
+
+    return this
+  }
+
   /**
    * Unregisters all probes and clears the timers.
    */
   public clear(): this {
     this.#timers.forEach(t => clearInterval(t))
     this.#timers = new Map()
+    this.removeAllListeners()
     return this
   }
 }