awaitify.js•816 B
'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = awaitify;
// conditionally promisify a function.
// only return a promise if a callback is omitted
function awaitify(asyncFn, arity) {
if (!arity) arity = asyncFn.length;
if (!arity) throw new Error('arity is undefined');
function awaitable(...args) {
if (typeof args[arity - 1] === 'function') {
return asyncFn.apply(this, args);
}
return new Promise((resolve, reject) => {
args[arity - 1] = (err, ...cbArgs) => {
if (err) return reject(err);
resolve(cbArgs.length > 1 ? cbArgs : cbArgs[0]);
};
asyncFn.apply(this, args);
});
}
return awaitable;
}
module.exports = exports.default;