fix: removeListener (#95)

event-handler/remove-listener.js

@@ -14,7 +14,7 @@ function receiverListener (state, webhookNameOrNames, handler) {
 
   // remove last hook that has been added, that way
   // it behaves the same as removeListener
-  for (let i = state.hooks[webhookNameOrNames].length; i > 0; i--) {
+  for (let i = state.hooks[webhookNameOrNames].length - 1; i >= 0; i--) {
     if (state.hooks[webhookNameOrNames][i] === handler) {
       state.hooks[webhookNameOrNames].splice(i, 1)
       return

test/unit/event-handler-remove-listener-test.js

@@ -0,0 +1,42 @@
+const test = require('tap').test
+
+const removeListener = require('../../event-handler/remove-listener')
+
+test('remove-listener: single listener', t => {
+  const push = () => {}
+
+  const state = {
+    hooks: {
+      push: [push]
+    }
+  }
+
+  t.doesNotThrow(() => {
+    removeListener(state, 'push', push)
+  })
+  t.deepEqual(state, { hooks: { push: [] } })
+  t.end()
+})
+
+test('remove-listener: multiple listeners', t => {
+  const push1 = () => {}
+  const push2 = () => {}
+  const push3 = () => {}
+
+  const ping = () => {}
+
+  const state = {
+    hooks: {
+      push: [push1, push2, push3],
+      ping: [ping]
+    }
+  }
+
+  t.doesNotThrow(() => {
+    removeListener(state, 'push', push1)
+    removeListener(state, 'push', push2)
+    removeListener(state, 'push', push3)
+  })
+  t.deepEqual(state, { hooks: { push: [], ping: [ping] } })
+  t.end()
+})