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31 lines
896 B
JavaScript
31 lines
896 B
JavaScript
6 years ago
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'use strict';
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.default = awaitify;
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// conditionally promisify a function.
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// only return a promise if a callback is omitted
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function awaitify(asyncFn, arity = asyncFn.length) {
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if (!arity) throw new Error('arity is undefined');
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function awaitable(...args) {
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if (typeof args[arity - 1] === 'function') {
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return asyncFn.apply(this, args);
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}
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return new Promise((resolve, reject) => {
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args[arity - 1] = (err, ...cbArgs) => {
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if (err) return reject(err);
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resolve(cbArgs.length > 1 ? cbArgs : cbArgs[0]);
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};
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asyncFn.apply(this, args);
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});
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}
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Object.defineProperty(awaitable, 'name', {
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value: `awaitable(${asyncFn.name})`
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});
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return awaitable;
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}
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module.exports = exports['default'];
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