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Diffstat (limited to 'common/once.mjs')
-rw-r--r-- | common/once.mjs | 42 |
1 files changed, 0 insertions, 42 deletions
diff --git a/common/once.mjs b/common/once.mjs deleted file mode 100644 index 0f76366..0000000 --- a/common/once.mjs +++ /dev/null @@ -1,42 +0,0 @@ -/** -* 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; |