31 lines
1.1 KiB
TypeScript
31 lines
1.1 KiB
TypeScript
// Copyright 2017-2021 @polkadot/util authors & contributors
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// SPDX-License-Identifier: Apache-2.0
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/**
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* @name promisify
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* @summary Wraps an async callback into a `Promise`
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* @description
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* Wraps the supplied async function `fn` that has a standard JS callback `(error: Error, result: any)` into a `Promise`, passing the supplied parameters. When `error` is set, the Promise is rejected, else the Promise resolves with the `result` value.
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* @example
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* <BR>
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*
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* ```javascript
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* const { promisify } from '@polkadot/util';
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*
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* await promisify(null, ((a, cb) => cb(null, a), true); // resolves with `true`
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* await promisify(null, (cb) => cb(new Error('error!'))); // rejects with `error!`
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* ```
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*/
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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export function promisify <R = any> (self: unknown, fn: (...params: any) => any, ...params: any[]): Promise<R> {
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return new Promise((resolve, reject): void => {
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fn.apply(self, params.concat((error: Error | null, result?: R): void => {
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if (error) {
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reject(error);
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} else {
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resolve(result as R);
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}
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}));
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});
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}
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