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'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = asyncify;
var _isObject = require('lodash/isObject');
var _isObject2 = _interopRequireDefault(_isObject);
var _initialParams = require('./internal/initialParams');
var _initialParams2 = _interopRequireDefault(_initialParams);
var _setImmediate = require('./internal/setImmediate');
var _setImmediate2 = _interopRequireDefault(_setImmediate);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
/**
* Take a sync function and make it async, passing its return value to a
* callback. This is useful for plugging sync functions into a waterfall,
* series, or other async functions. Any arguments passed to the generated
* function will be passed to the wrapped function (except for the final
* callback argument). Errors thrown will be passed to the callback.
*
* If the function passed to `asyncify` returns a Promise, that promises's
* resolved/rejected state will be used to call the callback, rather than simply
* the synchronous return value.
*
* This also means you can asyncify ES2017 `async` functions.
*
* @name asyncify
* @static
* @memberOf module:Utils
* @method
* @alias wrapSync
* @category Util
* @param {Function} func - The synchronous function, or Promise-returning
* function to convert to an {@link AsyncFunction}.
* @returns {AsyncFunction} An asynchronous wrapper of the `func`. To be
* invoked with `(args..., callback)`.
* @example
*
* // passing a regular synchronous function
* async.waterfall([
* async.apply(fs.readFile, filename, "utf8"),
* async.asyncify(JSON.parse),
* function (data, next) {
* // data is the result of parsing the text.
* // If there was a parsing error, it would have been caught.
* }
* ], callback);
*
* // passing a function returning a promise
* async.waterfall([
* async.apply(fs.readFile, filename, "utf8"),
* async.asyncify(function (contents) {
* return db.model.create(contents);
* }),
* function (model, next) {
* // `model` is the instantiated model object.
* // If there was an error, this function would be skipped.
* }
* ], callback);
*
* // es2017 example, though `asyncify` is not needed if your JS environment
* // supports async functions out of the box
* var q = async.queue(async.asyncify(async function(file) {
* var intermediateStep = await processFile(file);
* return await somePromise(intermediateStep)
* }));
*
* q.push(files);
*/
function asyncify(func) {
return (0, _initialParams2.default)(function (args, callback) {
var result;
try {
result = func.apply(this, args);
} catch (e) {
return callback(e);
}
// if result is Promise object
if ((0, _isObject2.default)(result) && typeof result.then === 'function') {
result.then(function (value) {
invokeCallback(callback, null, value);
}, function (err) {
invokeCallback(callback, err.message ? err : new Error(err));
});
} else {
callback(null, result);
}
});
}
function invokeCallback(callback, error, value) {
try {
callback(error, value);
} catch (e) {
(0, _setImmediate2.default)(rethrow, e);
}
}
function rethrow(error) {
throw error;
}
module.exports = exports['default'];
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