aaac7fed
 liuqimichale
add
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'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = seq;
var _noop = require('lodash/noop');
var _noop2 = _interopRequireDefault(_noop);
var _slice = require('./internal/slice');
var _slice2 = _interopRequireDefault(_slice);
var _reduce = require('./reduce');
var _reduce2 = _interopRequireDefault(_reduce);
var _wrapAsync = require('./internal/wrapAsync');
var _wrapAsync2 = _interopRequireDefault(_wrapAsync);
var _arrayMap = require('lodash/_arrayMap');
var _arrayMap2 = _interopRequireDefault(_arrayMap);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
/**
* Version of the compose function that is more natural to read. Each function
* consumes the return value of the previous function. It is the equivalent of
* [compose]{@link module:ControlFlow.compose} with the arguments reversed.
*
* Each function is executed with the `this` binding of the composed function.
*
* @name seq
* @static
* @memberOf module:ControlFlow
* @method
* @see [async.compose]{@link module:ControlFlow.compose}
* @category Control Flow
* @param {...AsyncFunction} functions - the asynchronous functions to compose
* @returns {Function} a function that composes the `functions` in order
* @example
*
* // Requires lodash (or underscore), express3 and dresende's orm2.
* // Part of an app, that fetches cats of the logged user.
* // This example uses `seq` function to avoid overnesting and error
* // handling clutter.
* app.get('/cats', function(request, response) {
* var User = request.models.User;
* async.seq(
* _.bind(User.get, User), // 'User.get' has signature (id, callback(err, data))
* function(user, fn) {
* user.getCats(fn); // 'getCats' has signature (callback(err, data))
* }
* )(req.session.user_id, function (err, cats) {
* if (err) {
* console.error(err);
* response.json({ status: 'error', message: err.message });
* } else {
* response.json({ status: 'ok', message: 'Cats found', data: cats });
* }
* });
* });
*/
function seq() /*...functions*/{
var _functions = (0, _arrayMap2.default)(arguments, _wrapAsync2.default);
return function () /*...args*/{
var args = (0, _slice2.default)(arguments);
var that = this;
var cb = args[args.length - 1];
if (typeof cb == 'function') {
args.pop();
} else {
cb = _noop2.default;
}
(0, _reduce2.default)(_functions, args, function (newargs, fn, cb) {
fn.apply(that, newargs.concat(function (err /*, ...nextargs*/) {
var nextargs = (0, _slice2.default)(arguments, 1);
cb(err, nextargs);
}));
}, function (err, results) {
cb.apply(that, [err].concat(results));
});
};
}
module.exports = exports['default'];
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