fix(requestPermission): pass resolution callback

1) Safari doesn't return a promise when requestPermission is invoked. This was resulting in an error and the supplied resolution callback function was never called.

2) Additionally, Node v10 was promoted to LTS causing Travis CI to use it, resulting in a known bug: nodejs/node#20325 . This was fixed by specifying node v8 in travis config

Author: joshbeckman

.travis.yml

@@ -6,7 +6,7 @@ env:
   - secure: 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
 language: node_js
 node_js:
-- lts/*
+- "8.12"
 before_install: yarn global add greenkeeper-lockfile@1
 before_script:
 - curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64

src/push/Permission.js

@@ -41,13 +41,17 @@ export default class Permission {
     _requestWithCallback(onGranted: () => void, onDenied: () => void) {
         const existing = this.get();
 
+        var resolved = false;
         var resolve = (result = this._win.Notification.permission) => {
+            if (resolved) return;
+            resolved = true;
             if (typeof result === 'undefined' && this._win.webkitNotifications)
                 result = this._win.webkitNotifications.checkPermission();
             if (result === this.GRANTED || result === 0) {
                 if (onGranted) onGranted();
             } else if (onDenied) onDenied();
         };
+        var request;
 
         /* Permissions already set */
         if (existing !== this.DEFAULT) {
@@ -62,13 +66,16 @@ export default class Permission {
             this._win.Notification &&
             this._win.Notification.requestPermission
         ) {
-            /* Chrome 23+ */
-            this._win.Notification
-                .requestPermission()
-                .then(resolve)
-                .catch(function() {
+            /* Safari 12+ */
+            /* This resolve argument will only be used in Safari */
+            /* CHrome, instead, returns a Promise */
+            request = this._win.Notification.requestPermission(resolve);
+            if (request && request.then) {
+                /* Chrome 23+ */
+                request.then(resolve).catch(function() {
                     if (onDenied) onDenied();
                 });
+            }
         } else if (onGranted) {
             /* Let the user continue by default */
             onGranted();
@@ -97,8 +104,13 @@ export default class Permission {
             this._win.webkitNotifications.checkPermission;
 
         return new Promise((resolvePromise, rejectPromise) => {
-            var resolver = result =>
+            var resolved = false;
+            var resolver = result => {
+                if (resolved) return;
+                resolved = true;
                 isGranted(result) ? resolvePromise() : rejectPromise();
+            };
+            var request;
 
             if (hasPermissions) {
                 resolver(existing);
@@ -107,12 +119,14 @@ export default class Permission {
                     resolver(result);
                 });
             } else if (isModernAPI) {
-                this._win.Notification
-                    .requestPermission()
-                    .then(result => {
-                        resolver(result);
-                    })
-                    .catch(rejectPromise);
+                /* Safari 12+ */
+                /* This resolver argument will only be used in Safari */
+                /* CHrome, instead, returns a Promise */
+                request = this._win.Notification.requestPermission(resolver);
+                if (request && request.then) {
+                    /* Chrome 23+ */
+                    request.then(resolver).catch(rejectPromise);
+                }
             } else resolvePromise();
         });
     }