1 files changed, 62 insertions, 0 deletions
diff --git a/ext/js/core/promise-animation-frame.js b/ext/js/core/promise-animation-frame.js
new file mode 100644
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+++ b/ext/js/core/promise-animation-frame.js
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2023-2024  Yomitan Authors
+ * Copyright (C) 2019-2022  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Creates a promise that will resolve after the next animation frame, using `requestAnimationFrame`.
+ * @param {number} [timeout] A maximum duration (in milliseconds) to wait until the promise resolves. If null or omitted, no timeout is used.
+ * @returns {Promise<{time: number, timeout: boolean}>} A promise that is resolved with `{time, timeout}`, where `time` is the timestamp from `requestAnimationFrame`,
+ *   and `timeout` is a boolean indicating whether the cause was a timeout or not.
+ * @throws The promise throws an error if animation is not supported in this context, such as in a service worker.
+ */
+export function promiseAnimationFrame(timeout) {
+    return new Promise((resolve, reject) => {
+        if (typeof cancelAnimationFrame !== 'function' || typeof requestAnimationFrame !== 'function') {
+            reject(new Error('Animation not supported in this context'));
+            return;
+        }
+
+        /** @type {?import('core').Timeout} */
+        let timer = null;
+        /** @type {?number} */
+        let frameRequest = null;
+        /**
+         * @param {number} time
+         */
+        const onFrame = (time) => {
+            frameRequest = null;
+            if (timer !== null) {
+                clearTimeout(timer);
+                timer = null;
+            }
+            resolve({time, timeout: false});
+        };
+        const onTimeout = () => {
+            timer = null;
+            if (frameRequest !== null) {
+                cancelAnimationFrame(frameRequest);
+                frameRequest = null;
+            }
+            resolve({time: performance.now(), timeout: true});
+        };
+
+        frameRequest = requestAnimationFrame(onFrame);
+        if (typeof timeout === 'number') {
+            timer = setTimeout(onTimeout, timeout);
+        }
+    });
+}