Revision 261548ff
Added by koszko about 2 years ago
| common/once.js | ||
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* Redistribution terms are gathered in the `copyright' file. |
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*/ |
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"use strict"; |
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/* |
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* This module provides an easy way to wrap an async function into a promise |
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* so that it only gets executed once. |
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*/ |
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(() => {
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async function assign_result(state, result_producer) |
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{
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state.result = await result_producer(); |
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state.ready = true; |
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for (let cb of state.waiting) |
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setTimeout(cb, 0, state.result); |
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state.waiting = undefined; |
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} |
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async function assign_result(state, result_producer) |
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{
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state.result = await result_producer(); |
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state.ready = true; |
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for (let cb of state.waiting) |
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setTimeout(cb, 0, state.result); |
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state.waiting = undefined; |
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} |
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async function get_result(state)
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{
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if (state.ready)
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return state.result;
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async function get_result(state) |
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{
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if (state.ready)
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return state.result; |
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return new Promise((resolve, reject) => state.waiting.push(resolve));
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}
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return new Promise((resolve, reject) => state.waiting.push(resolve));
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} |
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function make_once(result_producer)
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{
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let state = {waiting : [], ready : false, result : undefined};
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assign_result(state, result_producer);
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return () => get_result(state);
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}
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function make_once(result_producer) |
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{
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let state = {waiting : [], ready : false, result : undefined};
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assign_result(state, result_producer);
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return () => get_result(state);
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} |
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window.make_once = make_once; |
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})(); |
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/* |
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* EXPORTS_START |
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* EXPORT make_once |
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* EXPORTS_END |
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*/ |
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Also available in: Unified diff
emply an sh-based build system; make some changes to blocking