Move `with_player` to a new module

Move this function to a new module as I'd like to use it for checking
the "Watch Credits" button.

Also change from a callback to a `Promise`. Need to include the
`Promise` lib via ES2015 in tsconfig to be able to build with promises.

3 files changed, 22 insertions, 15 deletions

diff --git a/src/fullscreen_credits.ts b/src/fullscreen_credits.ts
index 6d174ed..d8b68b9 100644
--- a/src/fullscreen_credits.ts
+++ b/src/fullscreen_credits.ts
@@ -1,17 +1,5 @@
-function with_player (callback) {
-	var interval = setInterval(
-		function() {
-			var player = document.querySelector('.NFPlayer.nf-player-container');
+import with_player from './player';
 
-			if (player) {
-				clearInterval(interval);
-
-				callback(player);
-			}
-		},
-		1000
-	);
-}
 
 function init_mutation_observer (player) {
 	var observer = new MutationObserver(function(mutation_list) {
@@ -60,7 +48,7 @@ function init_mutation_observer (player) {
 }
 
 export default function init () {
-	with_player(function(player) {
+	with_player().then(function(player) {
 		init_mutation_observer(player);
 	});
 }
diff --git a/src/player.ts b/src/player.ts
new file mode 100644
index 0000000..ea0e541
--- /dev/null
+++ b/src/player.ts
@@ -0,0 +1,16 @@
+export default function with_player (): Promise<HTMLElement> {
+	return new Promise(function(resolve) {
+		const interval = setInterval(
+			function() {
+				const player = document.querySelector('.NFPlayer.nf-player-container');
+
+				if (player) {
+					clearInterval(interval);
+
+					resolve(player);
+				}
+			},
+			1000
+		);
+	});
+}
diff --git a/tsconfig.json b/tsconfig.json
index 7dc02bd..c521338 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -3,7 +3,10 @@
 		"module": "commonjs",
 		"target": "ES5",
 		"outDir": "./build",
-		"sourceMap": true
+		"sourceMap": true,
+		"lib": [
+			"ES2015"
+		]
 	},
 	"files": [
 		"src/index.ts"