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+/**
+* Myext feature initialization promise
+*
+* Copyright (C) 2021 Wojtek Kosior
+*
+* Dual-licensed under:
+* - 0BSD license
+* - GPLv3 or (at your option) any later version
+*/
+
+"use strict";
+
+/*
+ * This module provides an easy way to wrap an async function into a promise
+ * so that it only gets executed once.
+ */
+
+async function assign_result(state, result_producer)
+{
+ state.result = await result_producer();
+ state.ready = true;
+ for (let cb of state.waiting)
+ setTimeout(cb, 0, state.result);
+ state.waiting = undefined;
+}
+
+async function get_result(state)
+{
+ if (state.ready)
+ return state.result;
+
+ return new Promise((resolve, reject) => state.waiting.push(resolve));
+}
+
+export function make_once(result_producer)
+{
+ let state = {waiting : [], ready : false, result : undefined};
+ assign_result(state, result_producer);
+ return () => get_result(state);
+}
+
+export default make_once;